ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Other Sources  (4,481)
  • AERODYNAMICS  (3,074)
  • SPACECRAFT PROPULSION AND POWER  (1,407)
  • Cell & Developmental Biology
  • Inorganic Chemistry
  • 1995-1999  (190)
  • 1985-1989  (4,283)
  • 1940-1944  (8)
Collection
Source
Keywords
Years
Year
  • 1
    facet.materialart.
    Unknown
    Experimental Studies of Flow Separation of the NACA 2412 Airfoil at Low Speeds (1997)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Wind tunnel tests have been conducted on an NACA 2412 airfoil section at Reynolds number of 2.2 x 10(exp 6) and Mach number of 0.13. Detailed measurements of flow fields associated with turbulent boundary layers have been obtained at angles of attack of 12.4 degrees, 14.4 degrees, and 16.4 degrees. Pre- and post-separated velocity and pressure survey results over the airfoil and in the associated wake are presented. Extensive force, pressure, tuft survey, hot-film survey, local skin friction, and boundary layer data are also included. Pressure distributions and separation point locations show good agreement with theory for the two layer angles of attack. Boundary layer displacement thickness, momentum thickness, and shape factor agree well with theory up to the point of separation. There is considerable disparity between extent of flow reversal in the wake as measured by pressure and hot-film probes. The difference is attributed to the intermittent nature of the flow reversal.
    Keywords: AERODYNAMICS
    Type: NASA-CR-197497 , NAS 1.26:197497 , AR77-3
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Implementation of a two-equation k-omega turbulence model in NPARC (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The implementation of a two-equation k-omega turbulence model into the NPARC flow solver is described. Motivation for the selection of this model is given, major code modifications are outlined, new imputs to the code are described, and results are presented for several validation cases: an incompressible flow over a smooth flat plate, a subsonic diffuser flow, and a shock-induced separated flow. Comparison of results with the k-epsilon model indicate that the k-omega model predicts simple flows equally well whereas, for adverse pressure gradient flows, the k-omega model outperforms the other turbulence models in NPARC.
    Keywords: AERODYNAMICS
    Type: NASA-TM-107080 , NAS 1.15:107080 , E-9955 , AIAA PAPER 96-0383 , NIPS-96-08118 , Aerospace Sciences Meeting and Exhibit; Jan 15, 1996 - Jan 18, 1996; Reno, NV; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    A mixed volume grid approach for the Euler and Navier-Stokes equations (1996)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An approach for solving the compressible Euler and Navier-Stokes equations upon meshes composed of nearly arbitrary polyhedra is described. Each polyhedron is constructed from an arbitrary number of triangular and quadrilateral face elements, allowing the unified treatment of tetrahedral, prismatic, pyramidal, and hexahedral cells, as well the general cut cells produced by Cartesian mesh approaches. The basics behind the numerical approach and the resulting data structures are described. The accuracy of the mixed volume grid approach is assessed by performing a grid refinement study upon a series of hexahedral, tetrahedral, prismatic, and Cartesian meshes for an analytic inviscid problem. A series of laminar validation cases are made, comparing the results upon differing grid topologies to each other, to theory, and experimental data. A computation upon a prismatic/tetrahedral mesh is made simulating the laminar flow over a wall/cylinder combination.
    Keywords: AERODYNAMICS
    Type: NASA-TM-107135 , NAS 1.15:107135 , AIAA PAPER 96-0762 , E-10065 , NIPS-96-07909 , Aerospace Sciences Meeting and Exhibit; Jan 15, 1996 - Jan 18, 1996; Reno, NV; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Buffeting tests in a cryogenic windtunnel (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Measurements of wing buffeting, using root strain gages, were made in the NASA Langley 0.3 m cryogenic wind tunnel to refine techniques which will be used in larger cryogenic facilities such as the United States National Transonic Facility (NTF) and the European Transonic Wind Tunnel (ETW). The questions addressed included the relative importance variations in frequency parameter and Reynolds number, the choice of model material (considering both stiffness and damping) and the effects of static aeroelastic distortion. The main series of tests was made on three half models of slender 65 deg delta wings with a sharp leading edge. The three delta wings had the same planform but widely differing bending stiffnesses and frequencies (obtained by varying both the material and the thickness of the wings). It was known that the steady flow on this configuration would be insensitive to variations in Reynolds number. On this wing at vortex breakdown the spectrum of the unsteady excitation is unusual, having a sharp peak at particular frequency parameter. Additional tests were made on one unswept half-wing of aspect ratio 1.5 with an NPL 9510 aerofoil section, known to be sensitive to variations in Reynolds number at transonic speeds. The test Mach numbers were M = 0.21 and 0.35 for the delta wings and to M = 0.30 for the unswept wing. On this wing the unsteady excitation spectrum is fairly flat (as on most wings). Hence correct representation of the frequency parameter is not particularly important.
    Keywords: AERODYNAMICS
    Type: Aeronautical Journal (ISSN 0001-9240); 99; 981; p. 1-14
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Analysis of shadowing effects on spacecraft power systems (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The orbiting shadowing analysis computer program was developed by NASA in order to assess the shadowing effects on various power systems. The algorithms, the inputs and outputs are discussed. Examples of typical shadowing analysis, performed for the International Space Station Freedom, the International Space Station Alpha and the joint United States/International Mir Solar Dynamic Flight Experimental Project are presented.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: ESA, Proceedings of 4th European Space Power Conference (ESPC). Volume 1: Power Systems, Power Electronics; p 297-302
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Raman scattering characterization of space solar cell structures (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: A contactless method for the determination of the free-carrier density and the composition distribution across the thickness of 3-5 multi-layer solar cell structures, using the Raman scattering method, is developed. The method includes a step analysis of Raman spectra from optical phonons and phonon-plasmon modes of different layers. The method provides simultaneous measurements of the element composition and the thickness of the structure's layers together with the free-carrier density. The results of measurements of the free-carrier density composition distributions of the liquid phase epitaxy grown AlGaAs/GaAs and GaSb solar cell structures are presented and discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: ESA, Proceedings of 4th European Space Power Conference (ESPC). Volume 2: Photovoltaic Generators, Energy Storage; p 645-648
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Flight data from the PASP-Plus experiment (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The photovoltaic array space power (PASP)-Plus solar cell flight experiment is described, and the observed performances of different solar cell types during the first six months of their operation, are summarized. The solar cell types include single crystal and amorphous silicon, GaAs, several multijunction cell types, indium phosphide and GaAs/GaSb concentrator cells. The radiation degradation experienced by some of the solar cell types agrees with theoretical predictions. Other samples, including silicon, are degraded less than predicted. Effects, including the increase in temperature of all the experiments and the effect of sun glint on cell measurement, are discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: ESA, Proceedings of 4th European Space Power Conference (ESPC). Volume 2: Photovoltaic Generators, Energy Storage; p 578-592
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Space photovoltaic modules based on reflective optics (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The conceptual design and experimental results for two types of space application concentrator photovoltaic modules, employing reflective optical elements, are presented. The first type is based on the use of compound parabolic concentrators, the second type is based on the use of line-focus parabolic troughs. Lightweight concentrators are formed with nickel foil coated silver with a diamond-like carbon layer protection. Secondary optical elements, including lenses and cones, are introduced for a better matching of concentrators and solar cells. Both types of modules are characterized by concentration ratios in the range 20x to 30x, depending on the chosen range of misorientation angles. The estimated specific parameters of these modules operating with single junction AlGaAs/GaAs solar cells are 240 W/sq m and 3 kg/sq m.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: ESA, Proceedings of 4th European Space Power Conference (ESPC). Volume 2: Photovoltaic Generators, Energy Storage; p 515-518
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Thermally stable, low resistance contact systems for use with shallow junction p(+) nn(+) and n(+)pp(+) InP solar cells (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Two contact systems for use on shallow junction InP solar cells are described. The feature shared by these two contact systems is the absence of the metallurgical intermixing that normally takes place between the semiconductor and the contact metallization during the sintering process. The n(+)pp(+) cell contact system, consisting of a combination of Au and Ge, not only exhibits very low resistance in the as-fabricated state, but also yields post-sinter resistivity values of 1(exp -7) ohms-sq cm, with effectively no metal-InP interdiffusion. The n(+)pp(+)cell contact system, consisting of a combination of Ag and Zn, permits low resistance ohmic contact to be made directly to a shallow junction p/n InP device without harming the device itself during the contacting process.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: ESA, Proceedings of 4th European Space Power Conference (ESPC). Volume 2: Photovoltaic Generators, Energy Storage; p 347-350
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    InGaAs/InP solar cells for space application (1995)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The effects of irradiation of In(0.53)Ga(0.47)As/InP (InGaAs/InP) solar cells illuminated through a transparent InP substrate with 1 MeV electrons were measured. These solar cells were developed for bottom cells in tandem solar photovoltaic cell structures. Some InGaAs/InP heterostructures with four layers were grown by liquid phase epitaxy. The structure of the solar cells allowed lightly doped materials in n and p photoactive layers to be used. The base dopant levels ranged from 1.10(exp 17) to 5.10(exp 17) cm(exp -3). The open circuit voltage and the short circuit current were moderately degraded after irradiation with 10(exp 16) cm(exp-2) 1 MeV electrons. This behavior is explained in terms of the device structure and the n and p layer thicknesses.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: ESA, Proceedings of 4th European Space Power Conference (ESPC). Volume 2: Photovoltaic Generators, Energy Storage; p 355-357
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 11
    facet.materialart.
    Unknown
    Arc tracking of cables for space applications (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The main objective of this study is to develop a new test method that is suitable for the assessment of the resistance of aerospace cables to arc tracking for different specific environmental and network conditions of spacecrafts. This paper reports the purpose, test conditions, test specimen, test procedure, and test acceptance criteria of seven different (200-250 mm long) cables.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Third NASA Workshop on Wiring for Space Applications; p 101-125
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 12
    facet.materialart.
    Unknown
    Comparison of arc tracking tests in various aerospace environments (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This report contains viewgraphs on arc tracking tests in various aerospace environments. It has the following six sections: LeRC arc tracking tests parameters, apparatus, sample description, procedure, arc tracking test results, and discussion.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Third NASA Workshop on Wiring for Space Applications; p 93-99
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 13
    facet.materialart.
    Unknown
    NASA Wiring for Space Applications Program: Fiscal year 1994 - 1995 testing activities (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The results of the testing of wire insulation materials for space applications is presented in this report. The wire insulations tested were partially fluorinated polyimide, extruded ETFE, extruded PTFE, PTFE tape, and PTFE/Kapton. The tests performed were flammability tests, odor tests, compatibility tests with aerospace fluids, offgassing tests, and thermal vacuum stability tests.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Third NASA Workshop on Wiring for Space Applications; p 69-84
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 14
    facet.materialart.
    Unknown
    NASA Wiring for Space Applications Program test results (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The objectives of the NASA Wiring for Space Applications program were to investigate the effects of atomic oxygen (AO), ultraviolet (UV) radiation, and AO with UV synergistic effects on wire insulation materials. The AO exposure was on the order of 10(exp 21) atoms/sq cm and the vacuum UV radiation was on the order of 10,000 ESH. The results of these tests are presented in this document
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Third NASA Workshop on Wiring for Space Applications; p 63-68
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 15
    facet.materialart.
    Unknown
    NASA wiring for space applications program test results (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The electrical power wiring tests results from the NASA Wiring for Space Applications program are presented. The goal of the program was to develop a base for the building of a lightweight, arc track-resistant electrical wiring system for aerospace applications. This new wiring system would be applied to such structures as pressurized modules, trans-atmospheric vehicles, LEO/GEO environments, and lunar and Martian environments. Technological developments from this program include the fabrication of new insulating materials, the production of new wiring constructions, an improved system design, and an advanced circuit protection design.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Third NASA Workshop on Wiring for Space Applications; p 57-62
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 16
    facet.materialart.
    Unknown
    Investigation of cleanliness verification techniques for rocket engine hardware (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Oxidizer propellant systems for liquid-fueled rocket engines must meet stringent cleanliness requirements for particulate and nonvolatile residue. These requirements were established to limit residual contaminants which could block small orifices or ignite in the oxidizer system during engine operation. Limiting organic residues in high pressure oxygen systems is particularly important. The current method of cleanliness verification used by Rocketdyne requires an organic solvent flush of the critical hardware surfaces. The solvent is filtered and analyzed for particulate matter, followed by gravimetric determination of the nonvolatile residue (NVR) content of the filtered solvent. The organic solvents currently specified for use (1,1,1-trichloroethane and CFC-113) are ozone-depleting chemicals slated for elimination by December 1995. A test program is in progress to evaluate alternative methods for cleanliness verification that do not require the use of ozone-depleting chemicals and that minimize or eliminate the use of solvents regulated as hazardous air pollutants or smog precursors. Initial results from the laboratory test program to evaluate aqueous-based methods and organic solvent flush methods for NVR verification are provided and compared with results obtained using the current method. Evaluation of the alternative methods was conducted using a range of contaminants encountered in the manufacture of rocket engine hardware.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Marshall Space Flight Center, Aerospace Environmental Technology Conference; p 593-602
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 17
    facet.materialart.
    Unknown
    Marshall Space Flight Center surface modeling and grid generation applications (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Solid Rocket Motors (SRM) used by NASA to propel the Space Shuttle employ gimballing nozzles as a means for vehicular guidance during launch and ascent. Gimballing a nozzle renders the pressure field of the exhaust gases nonaxisymmetric. This has two effects: (1) it exerts a torque and side load on the nozzle; and (2) the exhaust gases flow circumferentially in the aft-dome region, thermally loading the flexible boot, case-to-nozzle joint, and casing insulation. The use of CFD models to simulate such flows is imperative in order to assess SRM design. The grids for these problems were constructed by obtaining information from drawings and tabulated coordinates. The 2D axisymmetric grids were designed and generated using the EZ-Surf and GEN2D surface and grid generation codes. These 2D grids were solved using codes such as FDNS, GASP, and MINT. These axisymmetric grids were rotated around the center-line to form 3D nongimballed grids. These were then gimballed around the pivot point and the gaps or overlaps resurfaced to obtain the final domains, which contained approximately 366,000 grid points. The 2D solutions were then rotated and manipulated as appropriate for geometry and used as initial guesses in the final solution. The analyses were used in answering questions about flight criteria.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 105-120
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 18
    facet.materialart.
    Unknown
    Preliminary analysis of dynamic stall effects on a 91-meter wind turbine rotor (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Analytical investigation of dynamic stall on HAWT (horizontal-axis wind turbines) rotor loads was conducted. Dynamic stall was modeled using the Gormont approach on the MOD-2 rotor, treating the blade as a rigid body teetering about a fixed axis. Blade flapwise bending moments at station 370 were determined with and without dynamic stall for spatial variations in local wind speed due to wind shear and yaw. The predicted mean flapwise bending moments were found to be in good agreement with test results. Results obtained with and without dynamic stall showed no significant difference for the mean flapwise bending moment. The cyclic bending moments calculated with and without dynamic stall effects were substantially the same. None of the calculated cyclic loads reached the level of the cyclic loads measured on the MOD-2 using the Boeing five-minute-average technique.
    Keywords: AERODYNAMICS
    Type: DASCON Engineering, Collected Papers on Wind Turbine Technology; p 41-46
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 19
    facet.materialart.
    Unknown
    Technology transfer into the solid propulsion industry (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: This paper is a survey of the waste minimization efforts of industries outside of aerospace for possible applications in the manufacture of solid rocket motors (SRM) for NASA. The Redesigned Solid Rocket Motor (RSRM) manufacturing plan was used as the model for processes involved in the production of an SRM. A literature search was conducted to determine the recycling, waste minimization, and waste treatment methods used in the commercial sector that might find application in SRM production. Manufacturers, trade organizations, and professional associations were also contacted. Waste minimization efforts for current processes and replacement technologies, which might reduce the amount or severity of the wastes generated in SRM production, were investigated. An overview of the results of this effort are presented in this paper.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Marshall Space Flight Center, Aerospace Environmental Technology Conference; p 123-129
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 20
    facet.materialart.
    Unknown
    An unstructured-grid software system for solving complex aerodynamic problems (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A coordinated effort has been underway over the past four years to elevate unstructured-grid methodology to a mature level. The goal of this endeavor is to provide a validated capability to non-expert users for performing rapid aerodynamic analysis and design of complex configurations. The Euler component of the system is well developed, and is impacting a broad spectrum of engineering needs with capabilities such as rapid grid generation and inviscid flow analysis, inverse design, interactive boundary layers, and propulsion effects. Progress is also being made in the more tenuous Navier-Stokes component of the system. A robust grid generator is under development for constructing quality thin-layer tetrahedral grids, along with a companion Navier-Stokes flow solver. This paper presents an overview of this effort, along with a perspective on the present and future status of the methodology.
    Keywords: AERODYNAMICS
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 289-308
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 21
    facet.materialart.
    Unknown
    RTE: A computer code for Rocket Thermal Evaluation (1995)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The numerical model for a rocket thermal analysis code (RTE) is discussed. RTE is a comprehensive thermal analysis code for thermal analysis of regeneratively cooled rocket engines. The input to the code consists of the composition of fuel/oxidant mixture and flow rates, chamber pressure, coolant temperature and pressure. dimensions of the engine, materials and the number of nodes in different parts of the engine. The code allows for temperature variation in axial, radial and circumferential directions. By implementing an iterative scheme, it provides nodal temperature distribution, rates of heat transfer, hot gas and coolant thermal and transport properties. The fuel/oxidant mixture ratio can be varied along the thrust chamber. This feature allows the user to incorporate a non-equilibrium model or an energy release model for the hot-gas-side. The user has the option of bypassing the hot-gas-side calculations and directly inputting the gas-side fluxes. This feature is used to link RTE to a boundary layer module for the hot-gas-side heat flux calculations.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, The Sixth Annual Thermal and Fluids Analysis Workshop; p 141-162
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 22
    facet.materialart.
    Unknown
    High performance nickel electrodes for space power applications (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The specific energy density and the performance of nickel electrodes are generally limited by the electrode microstructure and the nature of the active material within the electrode matrix. Progress is being made in our laboratory in a collaborative effort with NASA-LEWIS Research Center to develop lighter weight, mechanically stable and highly efficient nickel electrodes for aerospace applications. Our approach is based on an electrode microstructure fabricated from a mixture of nickel fibers as small as 2 micro m diameter and cellulose fibers. Results will be presented to show the optimum conditions for impregnating this electrode microstructure with nickel hydroxide active material. Performance data in half-cell tests and cycle life data will also be presented. The flexibility of this electrode microstructure and the significant advantages it offers in terms of weight and performance will be demonstrated, in particular its ability to accept charge at high rates and to discharge at high rates.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Space Electrochemical Research and Technology. Abstracts; p 5
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 23
    facet.materialart.
    Unknown
    Algorithms for high aspect ratio oriented triangulations (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: Grid generation plays an integral part in the solution of computational fluid dynamics problems for aerodynamics applications. A major difficulty with standard structured grid generation, which produces quadrilateral (or hexahedral) elements with implicit connectivity, has been the requirement for a great deal of human intervention in developing grids around complex configurations. This has led to investigations into unstructured grids with explicit connectivities, which are primarily composed of triangular (or tetrahedral) elements, although other subdivisions of convex cells may be used. The existence of large gradients in the solution of aerodynamic problems may be exploited to reduce the computational effort by using high aspect ratio elements in high gradient regions. However, the heuristic approaches currently in use do not adequately address this need for high aspect ratio unstructured grids. High aspect ratio triangulations very often produce the large angles that are to be avoided. Point generation techniques based on contour or front generation are judged to be the most promising in terms of being able to handle complicated multiple body objects, with this technique lending itself well to adaptivity. The eventual goal encompasses several phases: first, a partitioning phase, in which the Voronoi diagram of a set of points and line segments (the input set) will be generated to partition the input domain; second, a contour generation phase in which body-conforming contours are used to subdivide the partition further as well as introduce the foundation for aspect ratio control, and; third, a Steiner triangulation phase in which points are added to the partition to enable triangulation while controlling angle bounds and aspect ratio. This provides a combination of the advancing front/contour techniques and refinement. By using a front, aspect ratio can be better controlled. By using refinement, bounds on angles can be maintained, while attempting to minimize the number of Steiner points.
    Keywords: AERODYNAMICS
    Type: NASA. Lewis Research Center, Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions; p 88
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 24
    facet.materialart.
    Unknown
    Development of advanced Si and GaAs solar cells for interplanetary missions (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The deep space and planetary exploration project have been acquiring more and more importance and some of them are now well established both in ESA and NASA programs. This paper presents the possibility to utilize both silicon and gallium arsenide solar cells as spacecraft primary power source for missions far from the Sun, in order to overcome the drawbacks related to the utilisation of radioisotope thermoelectric generators - such as cost, safety and social acceptance. The development of solar cells for low illumination intensity and low temperature (LILT) applications is carried out in Europe by ASE (Germany) and CISE (Italy) in the frame of an ESA programme, aimed to provide the photovoltaic generators for ROSETTA: the cometary material investigation mission scheduled for launch in 2003. The LILT cells development and testing objectives are therefore focused on the following requirements: insolation intensity as low as 0.03 Solar Constant, low temperature down to -150 C and solar flare proton environment. At this stage of development, after the completion of the technology verification tests, it has been demonstrated that suitable technologies are available for the qualification of both silicon and gallium arsenide cells and both candidates have shown conversion efficiencies over 25% at an illumination of 0.03 SC and a temperature of -150 C. In particular, when measured at those LILT conditions, the newly developed 'Hl-ETA/NR-LILT' silicon solar cells have reached a conversion efficiency of 26.3%, that is the highest value ever measured on a single junction solar cell. A large quantity of both 'Hl-ETA/NR-LILT' silicon and 'GaAs/Ge-LILT' solar cells are presently under fabrication and they will be submitted to a qualification test plan, including radiation exposure, in order to verify their applicability with respect to the mission requirements. The availability of two valid options will minimize the risk for the very ambitious scientific project. The paper describes how the technical achievements have been possible with Si and GaAs LILT solar cells (including a comparison between measured and modelled l-V characteristics) and it presents the technology verification tests results.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Lewis Research Center, Proceedings of the 14th Space Photovoltaic Research and Technology Conference (SPRAT 14); p 6
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 25
    facet.materialart.
    Unknown
    Simulation of crossflow instability on a supersonic highly swept wing (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A direct numerical simulation (DNS) algorithm has been developed and validated for use in the investigation of crossflow instability on supersonic swept wings, an application of potential relevance to the design of the High-Speed Civil Transport (HSCT). The algorithm is applied to the investigation of stationary crossflow instability on an infinitely long 77-degree swept wing in Mach 3.5 flow. The results of the DNS are compared with the predictions of linear parabolized stability equation (PSE) methodology. In-general, the DNS and PSE results agree closely in terms of modal growth rate, structure, and orientation angle. Although further validation is needed for large-amplitude (nonlinear) disturbances, the close agreement between independently derived methods offers preliminary validation of both DNS and PSE approaches.
    Keywords: AERODYNAMICS
    Type: NASA-CR-198267 , NAS 1.26:198267 , NIPS-96-08486
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 26
    facet.materialart.
    Unknown
    Carbon-carbon grid for ion engines (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A method and apparatus of manufacturing a grid member for use in an ion discharge apparatus provides a woven carbon fiber in a matrix of carbon. The carbon fibers are orientated to provide a negatibe coefficient of thermal expansion for at least a portion of the grid member's operative range of use.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 27
    facet.materialart.
    Unknown
    Ground-recorded sonic boom signatures of F-18 aircraft formation flight (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Two F-18 aircraft were flown, one above the other, in two formations, in order for the shock systems of the two aircraft to merge and propagate to the ground. The first formation had the canopy of the lower F-18 in the inlet shock of the upper F-18 (called inlet-canopy). The flight conditions were Mach 1.22 and an altitude of 23,500 ft. An array of five sonic boom recorders was used on the ground to record the sonic boom signatures. This paper describes the flight test technique and the ground level sonic boom signatures. The tail-canopy formation resulted in two, separated, N-wave signatures. Such signatures probably resulted from aircraft positioning error. The inlet-canopy formation yielded a single modified signature; two recorders measured an approximate flattop signature. Loudness calculations indicated that the single inlet-canopy signatures were quieter than the two, separated tail-canopy signatures. Significant loudness occurs after a sonic boom signature. Such loudness probably comes from the aircraft engines.
    Keywords: AERODYNAMICS
    Type: NASA-TM-104312 , H-2067 , NAS 1.15:104312
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 28
    facet.materialart.
    Unknown
    Shape optimization of single- and two-element airfoils on multiblock grids (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A multiblock, discrete sensitivity analysis method is used to couple a direct optimization method and a flow analysis method. The domain is divided into smaller subdomains for which the sensitivities are obtained separately. Then, an effective sensitivity equation is solved to complete the coupling of all the sensitivity information. The flow analysis is based on the thin-layer Navier-Stokes equations solved by an implicit, upwind-biased, finite-volume method. The method of feasible directions is used for the present gradient-based optimization approach. First, a transonic airfoil is optimized to investigate the behavior of the method in highly nonlinear flows as well as the effect of different blocking strategies on the procedure. A supercritical airfoil is produced from an initially symmetric airfoil with multiblocking affecting the path but not the final shape. Secondly, a two-element airfoil is shape optimized in subsonic flow to demonstrate the present method's capability of shaping aerodynamically interfering elements simultaneously. For a very low and a very high Reynolds number cases, the shape of the main airfoil and the flap are optimized to yield improved lift-to-drag ratios.
    Keywords: AERODYNAMICS
    Type: NASA-CR-199785 , NAS 1.26:199785 , AIAA PAPER 94-4273 , NIPS-95-06444
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 29
    facet.materialart.
    Unknown
    Design geometry and design/off-design performance computer codes for compressors and turbines (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report summarizes some NASA Lewis (i.e., government owned) computer codes capable of being used for airbreathing propulsion system studies to determine the design geometry and to predict the design/off-design performance of compressors and turbines. These are not CFD codes; velocity-diagram energy and continuity computations are performed fore and aft of the blade rows using meanline, spanline, or streamline analyses. Losses are provided by empirical methods. Both axial-flow and radial-flow configurations are included.
    Keywords: AERODYNAMICS
    Type: NASA-CR-198433 , NAS 1.26:198433 , E-10041 , NIPS-95-06493
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 30
    facet.materialart.
    Unknown
    Analysis of advanced solid rocket motor ignition phenomena (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report presents the results obtained from an experimental analysis of the flow field in the slots of the star grain section in the head-end of the advanced solid rocket motor during the ignition transient. This work represents an extension of the previous tests and analysis to include the effects of using a center port in conjunction with multiple canted igniter ports. The flow field measurements include oil smear data on the star slot walls, pressure and heat transfer coefficient measurements on the star slot walls and velocity measurements in the star slot.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-199427 , NAS 1.26:199427
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 31
    facet.materialart.
    Unknown
    A far-wing line shape theory which satisfies the detailed balance principle (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A far-wing theory in which the validity of the detailed balance principle is maintained in each step of the derivation is presented. The role of the total density matrix including the initial correlations is analyzed rigorously. By factoring out the rapidly varying terms in the complex-time development operator in the interaction representation, better approximate expressions can be obtained. As a result, the spectral density can be expressed in terms of the line-coupling functions in which two coupled lines are arranged symmetrically and whose frequency detunings are omega - 1/2(omega(sub ji) + omega (sub j'i'). Using the approximate values omega - omega(sub ji) results in expressions that do not satisfy the detailed balance principle. However, this principle remains satisfied for the symmetrized spectral density in which not only the coupled lines are arranged symmetrically, but also the initial and final states belonging to the same lines are arranged symmetrically as well.
    Keywords: AERODYNAMICS
    Type: NASA-TM-111075 , NAS 1.15:111075
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 32
    facet.materialart.
    Unknown
    Low-speed longitudinal aerodynamic characteristics through poststall for 21 novel planform shapes (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: To identify planform characteristics which have promise for a highly maneuverable vehicle, an investigation was conducted in the Langley Subsonic Basic Research Tunnel to determine the low-speed longitudinal aerodynamics of 21 planform geometries. Concepts studied included twin bodies, double wings, cutout wings, and serrated forebodies. The planform models tested were all 1/4-in.-thick flat plates with beveled edges on the lower surface to ensure uniform flow separation at angle of attack. A 1.0-in.-diameter cylindrical metric body with a hemispherical nose was used to house the six-component strain gauge balance for each configuration. Aerodynamic force and moment data were obtained across an angle-of-attack range of 0 to 70 deg with zero sideslip at a free-stream dynamic pressure of 30 psf. Surface flow visualization studies were also conducted on selected configurations using fluorescent minitufts. Results from the investigation indicate that a cutout wing planform can improve lift characteristics; however, cutout size, shape, and position and wing leading-edge sweep will all influence the effectiveness of the cutout configuration. Tests of serrated forebodies identified this concept as an extremely effective means of improving configuration lift characteristics; increases of up to 25 percent in the value of maximum lift coefficient were obtained.
    Keywords: AERODYNAMICS
    Type: NASA-TP-3503 , L-17301 , NAS 1.60:3503
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 33
    facet.materialart.
    Unknown
    Radial and circumferential flow surveys at the inlet and exit of the Space Shuttle Main Engine High Pressure Fuel Turbine Model (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The main objective of this test was to obtain detailed radial and circumferential flow surveys at the inlet and exit of the SSME High Pressure Fuel Turbine model using three-hole cobra probes, hot-film probes, and a laser velocimeter. The test was designed to meet several objectives. First, the techniques for making laser velocimeter, hot-film probe, and cobra probe measurements in turbine flows were developed and demonstrated. The ability to use the cobra probes to obtain static pressure and, therefore, velocity had to be verified; insertion techniques had to be established for the fragile hot-film probes; and a seeding method had to be established for the laser velocimetry. Once the measurement techniques were established, turbine inlet and exit velocity profiles, temperature profiles, pressure profiles, turbulence intensities, and boundary layer thicknesses were measured at the turbine design point. The blockage effect due to the model inlet and exit total pressure and total temperature rakes on the turbine performance was also studied. A small range of off-design points were run to obtain the profiles and to verify the rake blockage effects off-design. Finally, a range of different Reynolds numbers were run to study the effect of Reynolds number on the various measurements.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NIPS-95-05521 , NASA-TM-111116 , NAS 1.15:111116
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 34
    facet.materialart.
    Unknown
    A computational fluid dynamics simulation of the hypersonic flight of the Pegasus(TM) vehicle using an artificial viscosity model and a nonlinear filtering method (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The computational fluid dynamics code, PARC3D, is tested to see if its use of non-physical artificial dissipation affects the accuracy of its results. This is accomplished by simulating a shock-laminar boundary layer interaction and several hypersonic flight conditions of the Pegasus(TM) launch vehicle using full artificial dissipation, low artificial dissipation, and the Engquist filter. Before the filter is applied to the PARC3D code, it is validated in one-dimensional and two-dimensional form in a MacCormack scheme against the Riemann and convergent duct problem. For this explicit scheme, the filter shows great improvements in accuracy and computational time as opposed to the nonfiltered solutions. However, for the implicit PARC3D code it is found that the best estimate of the Pegasus experimental heat fluxes and surface pressures is the simulation utilizing low artificial dissipation and no filter. The filter does improve accuracy over the artificially dissipative case but at a computational expense greater than that achieved by the low artificial dissipation case which has no computational time penalty and shows better results. For the shock-boundary layer simulation, the filter does well in terms of accuracy for a strong impingement shock but not as well for weaker shock strengths. Furthermore, for the latter problem the filter reduces the required computational time to convergence by 18.7 percent.
    Keywords: AERODYNAMICS
    Type: NASA-CR-186033 , H-2071 , NAS 1.26:186033
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 35
    facet.materialart.
    Unknown
    Solar thermal upper stage: Economic advantage and development status (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A solar thermal upper stage (STUS) is envisioned as a propulsive concept for the future. The STUS will be used for low Earth orbit (LEO) to geostationary-Earth orbit (GEO) transfer and for planetary exploration missions. The STUS offers significant performance gains over conventional chemical propulsion systems. These performance gains translate into a more economical, more efficient method of placing useful payloads in space and maximizing the benefits derived from space activity. This paper will discuss the economical advantages of an STUS compared to conventional chemical propulsion systems, the potential market for an STUS, and the recent activity in the development of an STUS. The results of this assessment combined with the performance gains, will provide a strong justification for the development of an STUS.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-111062 , NAS 1.15:111062
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 36
    facet.materialart.
    Unknown
    Development of multiobjective optimization techniques for sonic boom minimization (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An optimization procedure is developed for the simultaneous improvement of the aerodynamic and sonic boom characteristics of high speed aircraft. From a sonic boom perspective, it is desirable to minimize the first peak in the overpressure signal at a specified distance away from the aircraft. From aerodynamic point of view, the aerodynamic drag coefficient ratio must be minimized while maintaining the lift coefficient at desired level. The optimization procedure is applied to wing-body configurations related to high speed aircraft. The objectives of this current research are: (1) development of a multiobjective optimization procedure for aerospace vehicles with the integration of sonic boom and aerodynamic performance criteria; and (2) development of semi-analytical approach for calculating sonic boom design sensitivities.
    Keywords: AERODYNAMICS
    Type: NASA-CR-199083 , NAS 1.26:199083
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 37
    facet.materialart.
    Unknown
    Effect of wake structure on blade-vortex interaction phenomena: Acoustic prediction and validation (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: During the Higher Harmonic Control Aeroacoustic Rotor Test, extensive measurements of the rotor aerodynamics, the far-field acoustics, the wake geometry, and the blade motion for powered, descent, flight conditions were made. These measurements have been used to validate and improve the prediction of blade-vortex interaction (BVI) noise. The improvements made to the BVI modeling after the evaluation of the test data are discussed. The effects of these improvements on the acoustic-pressure predictions are shown. These improvements include restructuring the wake, modifying the core size, incorporating the measured blade motion into the calculations, and attempting to improve the dynamic blade response. A comparison of four different implementations of the Ffowcs Williams and Hawkings equation is presented. A common set of aerodynamic input has been used for this comparison.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110825 , NAS 1.15:110825 , AD-A294477
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 38
    facet.materialart.
    Unknown
    Analyzing rocket plume spectral data with neural networks (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The Optical Plume Anomaly Detection (OPAD) system is under development to provide early-warning failure detection in support of ground-level testing of the Space Shuttle Main Engine (SSME). Failure detection is to be achieved through the acquisition of spectrally resolved plume emissions and subsequent identification of abnormal levels indicative of engine corrosion or component failure. Two computer codes (one linear and the other non-linear) are used by the OPAD system to iteratively determine specific element concentrations in the SSME plume, given emission intensity and wavelength information. Since this analysis is extremely labor intensive, a study was initiated to develop neural networks that would model the 'inverse' of these computer codes. Optimally connected feed-forward networks with imperceptible prediction error have been developed for each element modeled by the linear code, SPECTRA4. Radial basis function networks were developed for the non-linear code, SPECTRA5, and predict combustion temperature in addition to element concentrations.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: AIAA PAPER 95-0997 , ; : The use of EOS for
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 39
    facet.materialart.
    Unknown
    SSME Post Test Diagnostic System: Systems Section (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An assessment of engine and component health is routinely made after each test firing or flight firing of a Space Shuttle Main Engine (SSME). Currently, this health assessment is done by teams of engineers who manually review sensor data, performance data, and engine and component operating histories. Based on review of information from these various sources, an evaluation is made as to the health of each component of the SSME and the preparedness of the engine for another test or flight. The objective of this project - the SSME Post Test Diagnostic System (PTDS) - is to develop a computer program which automates the analysis of test data from the SSME in order to detect and diagnose anomalies. This report primarily covers work on the Systems Section of the PTDS, which automates the analyses performed by the systems/performance group at the Propulsion Branch of NASA Marshall Space Flight Center (MSFC). This group is responsible for assessing the overall health and performance of the engine, and detecting and diagnosing anomalies which involve multiple components (other groups are responsible for analyzing the behavior of specific components). The PTDS utilizes several advanced software technologies to perform its analyses. Raw test data is analyzed using signal processing routines which detect features in the data, such as spikes, shifts, peaks, and drifts. Component analyses are performed by expert systems, which use 'rules-of-thumb' obtained from interviews with the MSFC data analysts to detect and diagnose anomalies. The systems analysis is performed using case-based reasoning. Results of all analyses are stored in a relational database and displayed via an X-window-based graphical user interface which provides ranked lists of anomalies and observations by engine component, along with supporting data plots for each.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-198375 , E-9829 , NAS 1.26:198375
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 40
    facet.materialart.
    Unknown
    Preliminary Design of a SP-100/Stirling Radiatively Coupled Heat Exchanger (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Several methods for coupling the SP-100 space nuclear reactor to the NASA Lewis Research Center's Free Piston Stirling Power Convertor (FPSPC) are presented. A 25 kWe, dual opposed Stirling convertor configuration is used in these designs. The concepts use radiative coupling between the SP-100 lithium loop and the sodium heat pipe of the Stirling convertor to transfer the heat from the reactor to the convertor. Four separate configurations are presented. Masses for the four designs vary from 41 to 176 kgs. Each design's structure, heat transfer characteristics, and heat pipe performance are analytically modeled.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-107069 , NAS 1.15:107069 , E-9933
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 41
    facet.materialart.
    Unknown
    Prediction and measurement of blade-vortex interaction loading (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An extensive quantity of airload measurements was obtained for a pressure-instrumented model of the BO-105 main rotor for a large number of higher-harmonic control (HHC) settings at Duits-Nederlandse Wind Tunnel (DNW). The wake geometry, vortex strength, and vortex core size were also measured through a laser light sheet technique and LDV. These results are used to verify the BVI airload prediction methodologies developed by AFDD, DLR, NASA Langley, and ONERA. The comparisons show that an accurate prediction of the blade motion and the wake geometry is the most important aspect of the BVI airload predictions.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110824 , NAS 1.15:110824 , AD-A294468
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 42
    facet.materialart.
    Unknown
    A guide to the use of the pressure disk rotor model as implemented in INS3D-UP (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This is a guide for the use of the pressure disk rotor model that has been placed in the incompressible Navier-Stokes code INS3D-UP. The pressure disk rotor model approximates a helicopter rotor or propeller in a time averaged manner and is intended to simulate the effect of a rotor in forward flight on the fuselage or the effect of a propeller on other aerodynamic components. The model uses a modified actuator disk that allows the pressure jump across the disk to vary with radius and azimuth. The cyclic and collective blade pitch angles needed to achieve a specified thrust coefficient and zero moment about the hub are predicted. The method has been validated with experimentally measured mean induced inflow velocities as well as surface pressures on a generic fuselage. Overset grids, sometimes referred to as Chimera grids, are used to simplify the grid generation process. The pressure disk model is applied to a cylindrical grid which is embedded in the grid or grids used for the rest of the configuration. This document will outline the development of the method, and present input and results for a sample case.
    Keywords: AERODYNAMICS
    Type: NASA-CR-4692 , NAS 1.26:4692
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 43
    facet.materialart.
    Unknown
    A perspective on computational aerothermodynamics: Current modeling difficulties (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Future hypersonic vehicles are going to be designed largely with computational fluid dynamic methods based on appropriate physical models. The question on how much of this design process can be completed with the present state of computational aerothermodynamics is addressed. Some limitations of current models are discussed. It is shown that much more research is required before it will be possible to accurately design a hypersonic vehicle for all of its flight conditions. The quantities that must be computed accurately so that a minimum weight hypersonic vehicle can be designed are discussed. The use of computational fluid dynamics methods coupled with current thermochemical models in order to compute the quantities under specific flow conditions is considered.
    Keywords: AERODYNAMICS
    Type: ESA, Proceedings of the 2nd European Symposium on Aerothermodynamics for Space Vehicles; p 365-37
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 44
    facet.materialart.
    Unknown
    Predicting engine parameters using the optic spectrum of the space shuttle main engine exhaust plume (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The Optical Plume Anomaly Detection (OPAD) system is under development to predict engine anomalies and engine parameters of the Space Shuttle's Main Engine (SSME). The anomaly detection is based on abnormal metal concentrations in the optical spectrum of the rocket plume. Such abnormalities could be indicative of engine corrosion or other malfunctions. Here, we focus on the second task of the OPAD system, namely the prediction of engine parameters such as rated power level (RPL) and mixture ratio (MR). Because of the high dimensionality of the spectrum, we developed a linear algorithm to resolve the optical spectrum of the exhaust plume into a number of separate components, each with a different physical interpretation. These components are used to predict the metal concentrations and engine parameters for online support of ground-level testing of the SSME. Currently, these predictions are labor intensive and cannot be done online. We predict RPL using neural networks and give preliminary results.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: AIAA PAPER 95-0954 , ; : The use of EOS for
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 45
    facet.materialart.
    Unknown
    Separation characteristics of generic stores from lee side of an inclined flat plate at Mach 6 (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An experimental investigation was conducted to determine the aerodynamic characteristics of a store as it was separated from the lee side of a flat plate inclined at 15 deg to the free-stream flow at Mach 6. Two store models were tested: a cone cylinder and a roof delta. Force and moment data were obtained for both stores as they were moved in 0.5-in. increments away from the flat plate lee-side separated flow region into the free-stream flow while the store angle of attack was held constant at either 0 deg or 15 deg. The results indicate that both stores had adverse separation characteristics (i.e., negative normal force and pitching moment) at an angle of attack of 0 deg, and the cone cylinder had favorable separation characteristics (i.e., positive normal force and pitching moment) at an angle of attack of 15 deg. At an angle of attack of 15 deg, the separation characteristics of the roof delta are indeterminate at small separation distances and favorable at greater separation distances. These characteristics are the result of the local flow inclination relative to the stores as they traversed through the flat plate lee-side flow field. In addition to plotted data, force and moment data are tabulated and schlieren photographs of the stores and flat plate are presented.
    Keywords: AERODYNAMICS
    Type: NASA-TM-4652 , L-17384 , NAS 1.15:4652
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 46
    facet.materialart.
    Unknown
    A longitudinal aerodynamic data repeatability study for a commercial transport model test in the National Transonic Facility (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A high Reynolds number investigation of a commercial transport model was conducted in the National Transonic Facility (NTF) at Langley Research Center. This investigation was part of a cooperative effort to test a 0.03-scale model of a Boeing 767 airplane in the NTF over a Mach number range of 0.70 to 0.86 and a Reynolds number range of 2.38 to 40.0 x 10(exp 6) based on the mean aerodynamic chord. One of several specific objectives of the current investigation was to evaluate the level of data repeatability attainable in the NTF. Data repeatability studies were performed at a Mach number of 0.80 with Reynolds numbers of 2.38, 4.45, and 40.0 x 10(exp 6) and also at a Mach number of 0.70 with a Reynolds number of 40.0 x 10(exp 6). Many test procedures and data corrections are addressed in this report, but the data presented do not include corrections for wall interference, model support interference, or model aeroelastic effects. Application of corrections for these three effects would not affect the results of this study because the corrections are systematic in nature and are more appropriately classified as sources of bias error. The repeatability of the longitudinal stability-axis force and moment data has been accessed. Coefficients of lift, drag, and pitching moment are shown to repeat well within the pretest goals of plus or minus 0.005, plus or minus 0.0001, and plus or minus 0.001, respectively, at a 95-percent confidence level over both short- and near-term periods.
    Keywords: AERODYNAMICS
    Type: NASA-TP-3522 , L-17412 , NAS 1.60:3522
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 47
    facet.materialart.
    Unknown
    Fundamental phenomena on fuel decomposition and boundary-layer combustion processes with applications to hybrid rocket motors (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The experimental study on the fundamental processes involved in fuel decomposition and boundary-layer combustion in hybrid rocket motors is continuously being conducted at the High Pressure Combustion Laboratory of The Pennsylvania State University. This research will provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high-pressure, 2-D slab motor has been designed, manufactured, and utilized for conducting seven test firings using HTPB fuel processed at PSU. A total of 20 fuel slabs have been received from the Mcdonnell Douglas Aerospace Corporation. Ten of these fuel slabs contain an array of fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. Diagnostic instrumentation used in the test include high-frequency pressure transducers for measuring static and dynamic motor pressures and fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. The ultrasonic pulse-echo technique as well as a real-time x-ray radiography system have been used to obtain independent measurements of instantaneous solid fuel regression rates.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-199126 , NAS 1.26:199126
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 48
    facet.materialart.
    Unknown
    Drag measurements of an axisymmetric nacelle mounted on a flat plate at supersonic speeds (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An experimental investigation was conducted to determine the effect of diverter wedge half-angle and nacelle lip height on the drag characteristics of an assembly consisting of a nacelle fore cowl from a typical high-speed civil transport (HSCT) and a diverter mounted on a flat plate. Data were obtained for diverter wedge half-angles of 4.0 deg, 6.0 deg, and 8.0 deg and ratios of the nacelle lip height above a flat plate to the boundary-layer thickness (h(sub n)/delta) of approximately 0.87 to 2.45. Limited drag data were also obtained on a complete nacelle/diverter configuration that included fore and aft cowls. Although the nacelle/diverter drag data were not corrected for base pressures or internal flow drag, the data are useful for comparing the relative drag of the configuration tested. The tests were conducted in the Langley Unitary Plan Wind Tunnel at Mach numbers of 1.50, 1.80, 2.10, and 2.40 and Reynolds numbers ranging from 2.00 x 10(exp 6) to 5.00 x 10(exp 6) per foot. The results of this investigation showed that the nacelle/diverter drag essentially increased linearly with increasing h(sub n)/delta except near 1.0 where the data showed a nonlinear behavior. This nonlinear behavior was probably caused by the interaction of the shock waves from the nacelle/diverter configuration with the flat-plate boundary layer. At the lowest h(sub n)/delta tested, the diverter wedge half-angle had virtually no effect on the nacelle/diverter drag. However, as h(sub n)/delta increased, the nacelle/diverter drag increased as diverter wedge half-angle increased.
    Keywords: AERODYNAMICS
    Type: NASA-TM-4660 , L-17416 , NAS 1.15:4660
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 49
    facet.materialart.
    Unknown
    Investigation of water droplet trajectories within the NASA icing research tunnel (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Water droplet trajectories within the NASA Lewis Research Center's Icing Research Tunnel (IRT) were studied through computer analysis. Of interest was the influence of the wind tunnel contraction and wind tunnel model blockage on the water droplet trajectories. The computer analysis was carried out with a program package consisting of a three-dimensional potential panel code and a three-dimensional droplet trajectory code. The wind tunnel contraction was found to influence the droplet size distribution and liquid water content distribution across the test section from that at the inlet. The wind tunnel walls were found to have negligible influence upon the impingement of water droplets upon a wing model.
    Keywords: AERODYNAMICS
    Type: NASA-TM-107023 , E-9828 , NAS 1.15:107023
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 50
    facet.materialart.
    Unknown
    SOFIA 2 model telescope wind tunnel test report (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This document outlines the tests performed to make aerodynamic force and torque measurements on the SOFIA wind tunnel model telescope. These tests were performed during the SOFIA 2 wind tunnel test in the 14 ft wind tunnel during the months of June through August 1994. The test was designed to measure the dynamic cross elevation moment acting on the SOFIA model telescope due to aerodynamic loading. The measurements were taken with the telescope mounted in an open cavity in the tail section of the SOFIA model 747. The purpose of the test was to obtain an estimate of the full scale aerodynamic disturbance spectrum, by scaling up the wind tunnel results (taking into account differences in sail area, air density, cavity dimension, etc.). An estimate of the full scale cross elevation moment spectrum was needed to help determine the impact this disturbance would have on the telescope positioning system requirements. A model of the telescope structure, made of a light weight composite material, was mounted in the open cavity of the SOFIA wind tunnel model. This model was mounted via a force balance to the cavity bulkhead. Despite efforts to use a 'stiff' balance, and a lightweight model, the balance/telescope system had a very low resonant frequency (37 Hz) compared to the desired measurement bandwidth (1000 Hz). Due to this mechanical resonance of the balance/telescope system, the balance alone could not provide an accurate measure of applied aerodynamic force at the high frequencies desired. A method of measurement was developed that incorporated accelerometers in addition to the balance signal, to calculate the aerodynamic force.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110668 , SER-PK-001 , NAS 1.15:110668
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 51
    facet.materialart.
    Unknown
    Performance of Partially Fluorinated Polyimide Insulation for Aerospace Applications (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Polyimide has been used extensively as the primary wiring insulation in commercial planes, military aircraft, and space vehicles due to its low weight, high service temperature, and good dielectric strength. New failure modes, however, have been associated with the use of polyimide because of the susceptibility of the insulation to pyrolization and arc tracking. A new wiring construction utilizing partially fluorinated polyimide insulation has been tested and compared with the standard military polyimide wire. Electrical properties which were investigated include AC corona inception and extinction voltages (sea level and 60,000 feet), time/current to smoke, and wire fusing time. The two constructions were also characterized in terms of their mechanical properties including abrasion resistance, dynamic cut through, and notch propagation. These test efforts and the results obtained are presented and discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-198372 , E-9820 , NAS 1.26:198372
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 52
    facet.materialart.
    Unknown
    Advanced analysis technique for the evaluation of linear alternators and linear motors (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A method for the mathematical analysis of linear alternator and linear motor devices and designs is described, and an example of its use is included. The technique seeks to surpass other methods of analysis by including more rigorous treatment of phenomena normally omitted or coarsely approximated such as eddy braking, non-linear material properties, and power losses generated within structures surrounding the device. The technique is broadly applicable to linear alternators and linear motors involving iron yoke structures and moving permanent magnets. The technique involves the application of Amperian current equivalents to the modeling of the moving permanent magnet components within a finite element formulation. The resulting steady state and transient mode field solutions can simultaneously account for the moving and static field sources within and around the device.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-198434 , NAS 1.26:198434 , E-10042 , NIPS-96-07533
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 53
    facet.materialart.
    Unknown
    Third NASA Workshop on Wiring for Space Applications (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This workshop addressed key technology issues in the field of electrical power wiring for space applications, and transferred information and technology related to space wiring for use in government and commercial applications. Speakers from space agencies, U.S. Federal labs, industry, and academia presented program overviews and discussed topics on arc tracking phenomena, advancements in insulation materials and constructions, and new wiring system topologies.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CP-10177 , NAS 1.55:10177 , E-9946 , NIPS-96-06247
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 54
    facet.materialart.
    Unknown
    A two dimensional interface element for coupling of independently modeled three dimensional finite element meshes and extensions to dynamic and non-linear regimes (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The work reported here pertains only to the first year of research for a three year proposal period. As a prelude to this two dimensional interface element, the one dimensional element was tested and errors were discovered in the code for built-up structures and curved interfaces. These errors were corrected and the benchmark Boeing composite crown panel was analyzed successfully. A study of various splines led to the conclusion that cubic B-splines best suit this interface element application. A least squares approach combined with cubic B-splines was constructed to make a smooth function from the noisy data obtained with random error in the coordinate data points of the Boeing crown panel analysis. Preliminary investigations for the formulation of discontinuous 2-D shell and 3-D solid elements were conducted.
    Keywords: AERODYNAMICS
    Type: NASA-CR-199951 , NAS 1.26:199951 , NIPS-96-07072
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 55
    facet.materialart.
    Unknown
    Flight test evaluation of the E-systems Differential GPS category 3 automatic landing system (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Test flights were conducted to evaluate the capability of Differential Global Positioning System (DGPS) to provide the accuracy and integrity required for International Civil Aviation Organization (ICAO) Category (CAT) III precision approach and landings. These test flights were part of a Federal Aviation Administration (FAA) program to evaluate the technical feasibility of using DGPS based technology for CAT III precision approach and landing applications. An IAI Westwind 1124 aircraft (N24RH) was equipped with DGPS receiving equipment and additional computing capability provided by E-Systems. The test flights were conducted at NASA Ames Research Center's Crows Landing Flight Facility, Crows Landing, California. The flight test evaluation was based on completing 100 approaches and landings. The navigation sensor error accuracy requirements were based on ICAO requirements for the Microwave Landing System (MLS). All of the approaches and landings were evaluated against ground truth reference data provided by a laser tracker. Analysis of these approaches and landings shows that the E-Systems DGPS system met the navigation sensor error requirements for a successful approach and landing 98 out of 100 approaches and landings, based on the requirements specified in the FAA CAT III Level 2 Flight Test Plan. In addition, the E-Systems DGPS system met the integrity requirements for a successful approach and landing or stationary trial for all 100 approaches and landings and all ten stationary trials, based on the requirements specified in the FAA CAT III Level 2 Flight Test Plan.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110368 , NAS 1.15:110368 , A-950096
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 56
    facet.materialart.
    Unknown
    Tables of properties of airfoil polynomials (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This monograph provides an extensive list of formulas for airfoil polynomials. These polynomials provide convenient expansion functions for the description of the downwash and pressure distributions of linear theory for airfoils in both steady and unsteady subsonic flow.
    Keywords: AERODYNAMICS
    Type: NASA-RP-1343 , L-17420 , NAS 1.61:1343
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 57
    facet.materialart.
    Unknown
    Numerical investigations in the backflow region of a vacuum plume (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Four tasks were completed in this period and results were published in AIAA papers. First, a Boltzmann-2D code, was developed and applied to compute MSFC-A2 nozzle/plume flow field. It solved the two-dimensional Boltzmann-BGK equation using the Finite Difference Discrete Ordinate (FDDO) numerical technique. The code was validated by experimental data for one-dimensional shock structure predictions, paper 95-2056. Successful results for nozzle/plume flow simulation using the developed Boltzmann-2D code were presented at the 1995 AIAA Aerospace Science Conference, paper 95-0627. Second, a computer code solving two-dimensional Burnett equations was developed and applied to low-density nozzle flow field calculation. Results were also published at the 1994 AIAA Thermophysics Conference, paper 94-2055. Third, the developed two-dimensional Burnett code was extended to compute axisymmetric flow field inside MSFC-A2 nozzle, paper 95-2008. The computed nozzle exit conditions are used as input data for Direct Simulation Monte Carlo (DSMC) plume calculation. Fourth, a DSMC code was modified to compute the exhausted plume near the nozzle exit and in the backflow region.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NIPS-95-05601 , NASA-CR-199642 , NAS 1.26:199642
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 58
    facet.materialart.
    Unknown
    Low-speed wind-tunnel investigation of a porous forebody and nose strakes for yaw control of a multirole fighter aircraft (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Low-speed wind-tunnel tests were conducted in the Langley 12-Foot Low-Speed Tunnel on a model of the Boeing Multirole Fighter (BMRF) aircraft. This single-seat, single-engine configuration was intended to be an F-16 replacement that would incorporate many of the design goals and advanced technologies of the F-22. Its mission requirements included supersonic cruise without afterburner, reduced observability, and the ability to attack both air-to-air and air-to-ground targets. So that it would be effective in all phases of air combat, the ability to maneuver at angles of attack up to and beyond maximum lift was also desired. Traditional aerodynamic yaw controls, such as rudders, are typically ineffective at these higher angles of attack because they are usually located in the wake from the wings and fuselage. For this reason, this study focused on investigating forebody-mounted controls that produces yawing moments by modifying the strong vortex flowfield being shed from the forebody at high angles of attack. Two forebody strakes were tested that varied in planform and chordwise location. Various patterns of porosity in the forebody skin were also tested that differed in their radial coverage and chordwise location. The tests were performed at a dynamic pressure of 4 lb/ft(exp 2) over an angle-of-attack range of -4 deg to 72 deg and a sideslip range of -10 deg to 10 deg. Static force data, static pressures on the surface of the forebody, and videotapes of flow-visualization using laser-illuminated smoke were obtained.
    Keywords: AERODYNAMICS
    Type: NASA-CR-4685 , NAS 1.26:4685
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 59
    facet.materialart.
    Unknown
    Utility aspects of space power: Load management versus source management (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Electrical power, as an area of study, is relatively young as compared to language, chemistry, physics, mathematics, philosophy, metallurgy, textiles, transportation, or farming. Practically all of the technology that has enabled the huge, continent-spanning power grids that have become ubiquitous in developed countries was developed in the last 150 years. In fact, Tesla's advocacy of alternating current for transmission just won out in the beginning of this century. Despite the novelty of the field as a whole, space power applications are, of course, much newer. This paper looks at the history of space power, and compares it to its older sibling on earth, forming a basis for determining appropriate transitions of technology from the terrestrial realm to space applications.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-108496 , NAS 1.15:108496
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 60
    facet.materialart.
    Unknown
    Vortex wakes of rotorcraft (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This paper presents an overview of the complex unsteady vortical flows that comprise the wakes of rotary-wing aircraft; of the effects these tangled vortical structures have on the performance, noise, and vibration; and of some of the recent attempts to measure, predict, and control the phenomena. The main points are illustrated with a number of examples from the recent literature and technical conferences.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110822 , NAS 1.15:110822 , AD-A294465
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 61
    facet.materialart.
    Unknown
    Pressure Distributions from Subsonic Tests of a NACA 0012 Semispan Wing Model (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An unswept, semispan wing model incorporating a NACA 0012 airfoil section was tested in the Langley 14- by 22-Foot Subsonic Tunnel. This report contains pressure data which document effects of wing configuration and free-stream conditions on wing pressure distributions. The untwisted wing incorporated a full-span, leading-edge Krueger flap and a full-span, single-slotted trailing-edge flap. The trailing-edge flap was tested at a deflection angle of 40 degrees and the Krueger flap at a deflection of 55 degrees. Three wing configurations were tested: cruise, trailing-edge flap only, and Knueger flap and trailing-edge flap deployed. Tests were conducted at free-stream dynamic pressures of 15, 30 and 60 psf, with corresponding chord Reynolds numbers of 1.22 to 2.11 million and Mach numbers of 0.12 to 0.20. Angles of attack presented range from 0 to 20 degrees, depending on wing configuration. The data are presented without analysis.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110148 , NAS 1.15:110148
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 62
    facet.materialart.
    Unknown
    Multidisciplinary design optimization using multiobjective formulation techniques (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report addresses the development of a multidisciplinary optimization procedure using an efficient semi-analytical sensitivity analysis technique and multilevel decomposition for the design of aerospace vehicles. A semi-analytical sensitivity analysis procedure is developed for calculating computational grid sensitivities and aerodynamic design sensitivities. Accuracy and efficiency of the sensitivity analysis procedure is established through comparison of the results with those obtained using a finite difference technique. The developed sensitivity analysis technique are then used within a multidisciplinary optimization procedure for designing aerospace vehicles. The optimization problem, with the integration of aerodynamics and structures, is decomposed into two levels. Optimization is performed for improved aerodynamic performance at the first level and improved structural performance at the second level. Aerodynamic analysis is performed by solving the three-dimensional parabolized Navier Stokes equations. A nonlinear programming technique and an approximate analysis procedure are used for optimization. The proceduredeveloped is applied to design the wing of a high speed aircraft. Results obtained show significant improvements in the aircraft aerodynamic and structural performance when compared to a reference or baseline configuration. The use of the semi-analytical sensitivity technique provides significant computational savings.
    Keywords: AERODYNAMICS
    Type: NASA-CR-199290 , NAS 1.26:199290
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 63
    facet.materialart.
    Unknown
    TROPIX Power System Architecture (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This document contains results obtained in the process of performing a power system definition study of the TROPIX power management and distribution system (PMAD). Requirements derived from the PMADs interaction with other spacecraft systems are discussed first. Since the design is dependent on the performance of the photovoltaics, there is a comprehensive discussion of the appropriate models for cells and arrays. A trade study of the array operating voltage and its effect on array bus mass is also presented. A system architecture is developed which makes use of a combination of high efficiency switching power convertors and analog regulators. Mass and volume estimates are presented for all subsystems.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-106660 , E-8975 , NAS 1.15:106660
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 64
    facet.materialart.
    Unknown
    Delta wing vortex manipulation using pulsed and steady blowing during ramp pitching (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The effectiveness of steady and pulsed blowing as a method of controlling delta wing vortices during ramp pitching has been investigated in flow visualization experiments conducted in a water tunnel. The recessed angled spanwise blowing technique was utilized for vortex manipulation. This technique was implemented on a beveled 60 delta wing using a pair of blowing ports located beneath the vortex core at 40% chord. The flow was injected primarily in the spanwise direction but was also composed of a component normal to the wing surface. The location of vortex burst was measured as a function of blowing intensity and pulsing frequency under static conditions, and the optimum blowing case was applied at three different wing pitching rates. Experimental results have shown that, when the burst location is upstream of the blowing port, pulsed blowing delays vortex breakdown in static and dynamic cases. Dynamic tests verified the existence of a hysteresis effect and demonstrated the improvements offered by pulsed blowing over both steady blowing and no-blowing scenarios. The application of blowing, at the optimum pulsing frequency, made the vortex breakdown location comparable in static and ramp pitch-up conditions.
    Keywords: AERODYNAMICS
    Type: NIPS-95-05494 , NASA-CR-199624 , NAS 1.26:199624 , AIAA PAPER 95-1817-CP , United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 65
    facet.materialart.
    Unknown
    The 3-D wake measurements near a hovering rotor for determining profile and induced drag (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Primarily an experimental effort, this study focuses on the velocity and vorticity fields in the near wake of a hovering rotor. Drag terminology is reviewed, and the theory for separately determining the profile-and-induced-drag components from wake quantities is introduced. Instantaneous visualizations of the flow field are used to center the laser velocimeter (LV) measurements on the vortex core and to assess the extent of the positional mandering of the trailing vortex. Velocity profiles obtained at different rotor speeds and distances behind the rotor blade clearly indicate the position, size, and rate of movement of the wake sheet and the core of the trailing vortex. The results also show the distribution of vorticity along the wake sheet and within the trailing vortex.
    Keywords: AERODYNAMICS
    Type: NASA-TP-3577 , A-950078 , NAS 1.60:3577 , ATCOM-TR-95-A-006
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 66
    facet.materialart.
    Unknown
    Numerical simulation of supersonic and hypersonic inlet flow fields (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report summarizes the research performed by North Carolina State University and NASA Ames Research Center under Cooperative Agreement NCA2-719, 'Numerical Simulation of Supersonic and Hypersonic Inlet Flow Fields". Four distinct rotated upwind schemes were developed and investigated to determine accuracy and practicality. The scheme found to have the best combination of attributes, including reduction to grid alignment with no rotation, was the cell centered non-orthogonal (CCNO) scheme. In 2D, the CCNO scheme improved rotation when flux interpolation was extended to second order. In 3D, improvements were less dramatic in all cases, with second order flux interpolation showing the least improvement over grid aligned upwinding. The reduction in improvement is attributed to uncertainty in determining optimum rotation angle and difficulty in performing accurate and efficient interpolation of the angle in 3D. The CCNO rotational technique will prove very useful for increasing accuracy when second order interpolation is not appropriate and will materially improve inlet flow solutions.
    Keywords: AERODYNAMICS
    Type: NASA-CR-199428 , NAS 1.26:199428
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 67
    facet.materialart.
    Unknown
    Aeroelastic stability of wind turbine blade/aileron systems (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Aeroelastic stability analyses have been performed for the MOD-5A blade/aileron system. Various configurations having different aileron torsional stiffness, mass unbalance, and control system damping have been investigated. The analysis was conducted using a code recently developed by the General Electric Company - AILSTAB. The code extracts eigenvalues for a three degree of freedom system, consisting of: (1) a blade flapwise mode; (2) a blade torsional mode; and (3) an aileron torsional mode. Mode shapes are supplied as input and the aileron can be specified over an arbitrary length of the blade span. Quasi-steady aerodynamic strip theory is used to compute aerodynamic derivatives of the wing-aileron combination as a function of spanwise position. Equations of motion are summarized herein. The program provides rotating blade stability boundaries for torsional divergence, classical flutter (bending/torsion) and wing/aileron flutter. It has been checked out against fixed-wing results published by Theodorsen and Garrick. The MOD-5A system is stable with respect to divergence and classical flutter for all practical rotor speeds. Aileron torsional stiffness must exceed a minimum critical value to prevent aileron flutter. The nominal control system stiffness greatly exceeds this minimum during normal operation. The basic system, however, is unstable for the case of a free (or floating) aileron. The instability can be removed either by the addition of torsional damping or mass-balancing the ailerons. The MOD-5A design was performed by the General Electric Company, Advanced Energy Program Department under Contract DEN3-153 with NASA Lewis Research Center and sponsored by the Department of Energy.
    Keywords: AERODYNAMICS
    Type: DASCON Engineering, Collected Papers on Wind Turbine Technology; p 99-114
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 68
    facet.materialart.
    Unknown
    Calculation of three-dimensional (3-D) internal flow by means of the velocity-vorticity formulation on a staggered grid (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A method has been developed to accurately compute the viscous flow in three-dimensional (3-D) enclosures. This method is the 3-D extension of a two-dimensional (2-D) method developed for the calculation of flow over airfoils. The 2-D method has been tested extensively and has been shown to accurately reproduce experimental results. As in the 2-D method, the 3-D method provides for the non-iterative solution of the incompressible Navier-Stokes equations by means of a fully coupled implicit technique. The solution is calculated on a body fitted computational mesh incorporating a staggered grid methodology. In the staggered grid method, the three components of vorticity are defined at the centers of the computational cell sides, while the velocity components are defined as normal vectors at the centers of the computational cell faces. The staggered grid orientation provides for the accurate definition of the vorticity components at the vorticity locations, the divergence of vorticity at the mesh cell nodes and the conservation of mass at the mesh cell centers. The solution is obtained by utilizing a fractional step solution technique in the three coordinate directions. The boundary conditions for the vorticity and velocity are calculated implicitly as part of the solution. The method provides for the non-iterative solution of the flow field and satisfies the conservation of mass and divergence of vorticity to machine zero at each time step. To test the method, the calculation of simple driven cavity flows have been computed. The driven cavity flow is defined as the flow in an enclosure driven by a moving upper plate at the top of the enclosure. To demonstrate the ability of the method to predict the flow in arbitrary cavities, results will he shown for both cubic and curved cavities.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110352 , A-950063 , NAS 1.15:110352
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 69
    facet.materialart.
    Unknown
    Automation based on knowledge modeling theory and its applications in engine diagnostic systems using Space Shuttle Main Engine vibrational data (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Humans can perform many complicated tasks without explicit rules. This inherent and advantageous capability becomes a hurdle when a task is to be automated. Modern computers and numerical calculations require explicit rules and discrete numerical values. In order to bridge the gap between human knowledge and automating tools, a knowledge model is proposed. Knowledge modeling techniques are discussed and utilized to automate a labor and time intensive task of detecting anomalous bearing wear patterns in the Space Shuttle Main Engine (SSME) High Pressure Oxygen Turbopump (HPOTP).
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-197983 , NAS 1.26:197983
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 70
    facet.materialart.
    Unknown
    Modeling of DC spacecraft power systems (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Future spacecraft power systems must be capable of supplying power to various loads. This delivery of power may necessitate the use of high-voltage, high-power dc distribution systems to transmit power from the source to the loads. Using state-of-the-art power conditioning electronics such as dc-dc converters, complex series and parallel configurations may be required at the interface between the source and the distribution system and between the loads and the distribution system. This research will use state-variables to model and simulate a dc spacecraft power system. Each component of the dc power system will be treated as a multiport network, and a state model will be written with the port voltages as the inputs. The state model of a component will be solved independently from the other components using its state transition matrix. A state-space averaging method is developed first in general for any dc-dc switching converter, and then demonstrated in detail for the particular case of the boost power stage. General equations for both steady-state (dc) and dynamic effects (ac) are obtained, from which important transfer functions are derived and applied to a special case of the boost power stage.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA. Johnson Space Center, National Aeronautics and Space Administration (NASA)(American Society for Engineering Education (ASEE) Summer Faculty Fellowship Program, 1994, Volume 1 9 p (SEE N95-32418; NASA. Johnson Space
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 71
    facet.materialart.
    Unknown
    Control of unsteady separated flow associated with the dynamic stall of airfoils (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An effort to understand and control the unsteady separated flow associated with the dynamic stall of airfoils was funded for three years through the NASA cooperative agreement program. As part of this effort a substantial data base was compiled detailing the effects various parameters have on the development of the dynamic stall flow field. Parameters studied include Mach number, pitch rate, and pitch history, as well as Reynolds number (through two different model chord lengths) and the condition of the boundary layer at the leading edge of the airfoil (through application of surface roughness). It was found for free stream Mach numbers as low as 0.4 that a region of supersonic flow forms on the leading edge of the suction surface of the airfoil at moderate angles of attack. The shocks which form in this supersonic region induce boundary-layer separation and advance the dynamic stall process. Under such conditions a supercritical airfoil profile is called for to produce a flow field having a weaker leading-edge pressure gradient and no leading-edge shocks. An airfoil having an adaptive-geometry, or dynamically deformable leading edge (DDLE), is under development as a unique active flow-control device. The DDLE, formed of carbon-fiber composite and fiberglass, can be flexed between a NACA 0012 profile and a supercritical profile in a controllable fashion while the airfoil is executing an angle-of-attack pitch-up maneuver. The dynamic stall data were recorded using point diffraction interferometry (PDI), a noninvasive measurement technique. A new high-speed cinematography system was developed for recording interferometric images. The system is capable of phase-locking with the pitching airfoil motion for real-time documentation of the development of the dynamic stall flow field. Computer-aided image analysis algorithms were developed for fast and accurate reduction of the images, improving interpretation of the results.
    Keywords: AERODYNAMICS
    Type: NASA-CR-198972 , NAS 1.26:198972 , MCAT-95-09
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 72
    facet.materialart.
    Unknown
    Numerical solution of the full potential equation using a chimera grid approach (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A numerical scheme utilizing a chimera zonal grid approach for solving the full potential equation in two spatial dimensions is described. Within each grid zone a fully-implicit approximate factorization scheme is used to advance the solution one interaction. This is followed by the explicit advance of all common zonal grid boundaries using a bilinear interpolation of the velocity potential. The presentation is highlighted with numerical results simulating the flow about a two-dimensional, nonlifting, circular cylinder. For this problem, the flow domain is divided into two parts: an inner portion covered by a polar grid and an outer portion covered by a Cartesian grid. Both incompressible and compressible (transonic) flow solutions are included. Comparisons made with an analytic solution as well as single grid results indicate that the chimera zonal grid approach is a viable technique for solving the full potential equation.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110360 , A-950082 , NAS 1.15:110360
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 73
    facet.materialart.
    Unknown
    Robust Rocket Engine Concept (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The potential for a revolutionary step in the durability of reusable rocket engines is made possible by the combination of several emerging technologies. The recent creation and analytical demonstration of life extending (or damage mitigating) control technology enables rapid rocket engine transients with minimum fatigue and creep damage. This technology has been further enhanced by the formulation of very simple but conservative continuum damage models. These new ideas when combined with recent advances in multidisciplinary optimization provide the potential for a large (revolutionary) step in reusable rocket engine durability. This concept has been named the robust rocket engine concept (RREC) and is the basic contribution of this paper. The concept also includes consideration of design innovations to minimize critical point damage.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-107010 , E-9794 , NAS 1.15:107010
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 74
    facet.materialart.
    Unknown
    Afterbody/nozzle pressure distributions of a twin-tail twin-engine fighter with axisymmetric nozzles at Mach numbers from 0.6 to 1.2 (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Distributions of static pressure coefficient over the afterbody and axisymmetric nozzles of a generic, twin-tail twin-engine fighter were obtained in the Langley 16-Foot Transonic Tunnel. The longitudinal positions of the vertical and horizontal tails were varied for a total of six aft-end configurations. Static pressure coefficients were obtained at Mach numbers between 0.6 and 1.2, angles of attack between 0 deg and 8 deg, and nozzle pressure ratios ranging from jet-off to 8. The results of this investigation indicate that the influence of the vertical and horizontal tails extends beyond the vicinity of the tail-afterbody juncture. The pressure distribution affecting the aft-end drag is influenced more by the position of the vertical tails than by the position of the horizontal tails. Transonic tail-interference effects are seen at lower free-stream Mach numbers at positive angles of attack than at an angle of attack of 0 deg.
    Keywords: AERODYNAMICS
    Type: NASA-TP-3509 , L-17438 , NAS 1.60:3509
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 75
    facet.materialart.
    Unknown
    Advanced small rocket chambers. Option 3: 110 1bf Ir-Re rocket, volume 2 (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This is the second part of a two-part report that describes the AJ10-221, a high performance iridium-coated rhenium (Ir-Re) 110 lbf (490N) welded rocket chamber with 286:1 area ratio nozzle. This engine was designed, built, and hot fired for over 6 hours on this program. It demonstrated an I(s) of 321.8 sec, which is 10 sec higher than conventional 110 lbf silicide coated Cb chambers now in use. The approach used in this portion of the program was to demonstrate the performance improvement that can be made by the elimination of fuel film cooling and the use of a high temperature (4000 F) (2200 C) iridium-coated rhenium (Ir-Re) rocket chamber. Detailed thermal, performance, mechanical, and dynamic design analyses of the full engine were conducted by Aerojet. Two Ir-Re chambers were built to the Aerojet design by Ultramet, using the chemical vapor deposition (CVD) process. Incorporation of a secondary mixing device or Boundary Layer Trip (BLT) within the combustion chamber (Aerojet Patents 4882904 and 4936091) results in improvement in flow uniformity, and a significant life and performance increase. The 110 lbf engine design was verified in bolt-up hardware tests at sea level and altitude. The effects of injector design on performance were studied. Two duplicate injectors were fabricated matching the preferred design and were demonstrated to be interchangeable in operation. One of these units were welded into a flight type thruster which was tested for an accumulated duration of 22,590 sec in 93 firings, one of which was a continuous burn of two hours. A design deficiency in the C-103 nozzle near the Re-Cb transition joint was discovered, studied and corrected design has been prepared. Workhardening studies have been conducted to investigate methods for increasing the low yield strength of the Re in the annealed conditions. An advanced 490N high performance engine has been demonstrated which, when proven to be capable of withstanding launch vibration, is ready for flight qualification.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-195435-VOL-2 , E-9457-VOL-2 , NAS 1.26:195435-VOL-2
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 76
    facet.materialart.
    Unknown
    Advanced Small Rocket Chambers. Option 3: 110 1Bf Ir-Re Rocket, Volume 1 (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report describes the AJ10-221, a high performance Iridium-coated Rhenium (Ir-Re) 110 lbf (490N) welded rocket chamber with 286:1 area ratio nozzle. This engine was designed, built, and hot fired for over 6 hours on this program. It demonstrated an I(s) of 321.8 sec, which is 10 sec higher than conventional 110 lbf silicide coated Cb chambers now in use. The approach used in this portion of the program was to demonstrate the performance improvement that can be made by the elimination of fuel film cooling and the use of a high temperature (4000F) (2200C) iridium-coated rhenium (Ir-Re) rocket chamber. Detailed thermal, performance, mechanical, and dynamic design analyses of the full engine were conducted by Aerojet. Two Ir-Re chambers were built to the Aerojet design by Ultramet, using the chemical vapor deposition (CVD) process. Incorporation of a secondary mixing device or Boundary Layer Trip (BLT) within the combustion chamber (Aerojet Patents 4882904 and 4936091) results in improvement in flow uniformity, and a significant life and performance increase. The 110 lbf engine design was verified in bolt-up hardware tests at sea level and altitude. The effects of injector design on performance were studied. Two duplicate injectors were fabricated matching the preferred design and were demonstrated to be interchangeable in operation. One of these units was fabricated matching the preferred design and was demonstrated to be interchangeable in operation. One of these units was welded into a flight type thruster which was tested for an accumulated duration of 22,590 sec in 93 firings, one of which was a continuous burn of two hours. A design deficiency in the C-103 nozzle near the Re-Cb transition joint was discovered, studied and corrected design has been prepared. Workhardening studies have been conducted to investigate methods for increasing the low yield strength of the Re in the annealed conditions. An advanced 490N high performance engine has been demonstrated which, when proven to be capable of withstanding launch vibration, is ready for flight qualification.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-195435-VOL-1 , E-9457-VOL-1 , NAS 1.26:195435-VOL-1
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 77
    facet.materialart.
    Unknown
    Experimental study of the effects of Reynolds number on high angle of attack aerodynamic characteristics of forebodies during rotary motion (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The National Aeronautics and Space Administration and the Defense Research Agency (United Kingdom) have ongoing experimental research programs in rotary-flow aerodynamics. A cooperative effort between the two agencies is currently underway to collect an extensive database for the development of high angle of attack computational methods to predict the effects of Reynolds number on the forebody flowfield at dynamic conditions, as well as to study the use of low Reynolds number data for the evaluation of high Reynolds number characteristics. Rotary balance experiments, including force and moment and surface pressure measurements, were conducted on circular and rectangular aftbodies with hemispherical and ogive noses at the Bedford and Farnborough wind tunnel facilities in the United Kingdom. The bodies were tested at 60 and 90 deg angle of attack for a wide range of Reynolds numbers in order to observe the effects of laminar, transitional, and turbulent flow separation on the forebody characteristics when rolling about the velocity vector.
    Keywords: AERODYNAMICS
    Type: NASA-CR-195033 , REPT-94-4 , NAS 1.26:195033
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 78
    facet.materialart.
    Unknown
    Performance of an aerodynamic yaw controller mounted on the space shuttle orbiter body flap at Mach 10 (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A wind-tunnel investigation of the effectiveness of an aerodynamic yaw controller mounted on the lower surface of a shuttle orbiter model body flap was conducted in the Langley 31-Inch Mach 10 Tunnel. The controller consisted of a 60 deg delta fin mounted perpendicular to the body flap lower surface and yawed 30 deg to the free stream direction. The control was tested at angles of attack from 20 deg to 40 deg at zero sideslip for a Reynolds number based on wing mean aerodynamic chord of 0.66 x 10(exp 6). The aerodynamic and control effectiveness characteristics are presented along with an analysis of the effectiveness of the controller in making a bank maneuver for Mach 18 flight conditions. The controller was effective in yaw and produced a favorable rolling moment. The analysis showed that the controller was as effective as the reaction control system in making the bank maneuver. These results warrant further studies of the aerodynamic/aerothermodynamic characteristics of the control concept for application to future transportation vehicles.
    Keywords: AERODYNAMICS
    Type: NASA-TM-109179 , NAS 1.15:109179
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 79
    facet.materialart.
    Unknown
    Aerodynamic optimization studies on advanced architecture computers (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The approach to carrying out multi-discipline aerospace design studies in the future, especially in massively parallel computing environments, comprises of choosing (1) suitable solvers to compute solutions to equations characterizing a discipline, and (2) efficient optimization methods. In addition, for aerodynamic optimization problems, (3) smart methodologies must be selected to modify the surface shape. In this research effort, a 'direct' optimization method is implemented on the Cray C-90 to improve aerodynamic design. It is coupled with an existing implicit Navier-Stokes solver, OVERFLOW, to compute flow solutions. The optimization method is chosen such that it can accomodate multi-discipline optimization in future computations. In the work , however, only single discipline aerodynamic optimization will be included.
    Keywords: AERODYNAMICS
    Type: NASA-CR-198045 , NAS 1.26:198045 , OMI-02-93
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 80
    facet.materialart.
    Unknown
    Enhanced analysis and users manual for radial-inflow turbine conceptual design code RTD (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Modeling enhancements made to a radial-inflow turbine conceptual design code are documented in this report. A stator-endwall clearance-flow model was added for use with pivoting vanes. The rotor calculations were modified to account for swept blades and splitter blades. Stator and rotor trailing-edge losses and a vaneless-space loss were added to the loss model. Changes were made to the disk-friction and rotor-clearance loss calculations. The loss model was then calibrated based on experimental turbine performance. A complete description of code input and output along with sample cases are included in the report.
    Keywords: AERODYNAMICS
    Type: NASA-CR-195454 , E-9538 , NAS 1.26:195454
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 81
    facet.materialart.
    Unknown
    Overview of the Solar Dynamic Ground Test Demonstration Program at the NASA Lewis Research Center (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the availability of SD technologies in a simulated space environment at the NASA Lewis Research Center (LERC) vacuum facility. Data from the SD GTD program will be provided to the joint U.S. and Russian team which is currently designing a 2 kW SD flight demonstration power system. This SD technology has the potential as a future power source for the International Space Station. This paper reviews the goals and status of the SD GTD program. A description of the SD GTD system includes key design features of the system, subsystems and components.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-106876 , E-9501 , NAS 1.15:106876
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 82
    facet.materialart.
    Unknown
    The acoustic characteristics of turbomachinery cavities (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Internal fluid flows are subject not only to self-sustained oscillations of the purely hydrodynamic type but also to the coupling of the instability with the acoustic mode of the surrounding cavity. This situation is common to turbomachinery, since flow instabilities are confined within a flow path where the acoustic wavelength is typically smaller than the dimensions of the cavity and flow speeds are low enough to allow resonances. When acoustic coupling occurs, the fluctuations can become so severe in amplitude that it may induce structural failure of engine components. The potential for catastrophic failure makes identifying flow-induced noise and vibration sources a priority. In view of the complexity of these types of flows, this report was written with the purpose of presenting many of the methods used to compute frequencies for self-sustained oscillations. The report also presents the engineering formulae needed to calculate the acoustic resonant modes for ducts and cavities. Although the report is not a replacement for more complex numerical or experimental modeling techniques, it is intended to be used on general types of flow configurations that are known to produce self-sustained oscillations. This report provides a complete collection of these models under one cover.
    Keywords: AERODYNAMICS
    Type: NASA-CR-4671 , M-778 , NAS 1.26:4671
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 83
    facet.materialart.
    Unknown
    Experimental results for a hypersonic nozzle/afterbody flow field (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This study was conducted to experimentally characterize the flow field created by the interaction of a single-expansion ramp-nozzle (SERN) flow with a hypersonic external stream. Data were obtained from a generic nozzle/afterbody model in the 3.5 Foot Hypersonic Wind Tunnel at the NASA Ames Research Center, in a cooperative experimental program involving Ames and McDonnell Douglas Aerospace. The model design and test planning were performed in close cooperation with members of the Ames computational fluid dynamics (CFD) team for the National Aerospace Plane (NASP) program. This paper presents experimental results consisting of oil-flow and shadow graph flow-visualization photographs, afterbody surface-pressure distributions, rake boundary-layer measurements, Preston-tube skin-friction measurements, and flow field surveys with five-hole and thermocouple probes. The probe data consist of impact pressure, flow direction, and total temperature profiles in the interaction flow field.
    Keywords: AERODYNAMICS
    Type: NASA-TM-4638 , A-94119 , NAS 1.15:4638
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 84
    facet.materialart.
    Unknown
    Numerical study to assess sulfur hexafluoride as a medium for testing multielement airfoils (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A methodology is described for computing viscous flows of air and sulfur hexafluoride (SF6). The basis is an existing flow solver that calculates turbulent flows in two dimensions on unstructured triangular meshes. The solver has been modified to incorporate the thermodynamic model for SF6 and used to calculate the viscous flow over two multielement airfoils that have been tested in a wind tunnel with air as the test medium. Flows of both air and SF6 at a free-stream Mach number of 0.2 and a Reynolds number of 9 x 10(exp 6) are computed for a range of angles of attack corresponding to the wind-tunnel test. The computations are used to investigate the suitability of SF6 as a test medium in wind tunnels and are a follow-on to previous computations for single-element airfoils. Surface-pressure, lift, and drag coefficients are compared with experimental data. The effects of heavy gas on the details of the flow are investigated based on computed boundary-layer and skin-friction data. In general, the predictions in SF6 vary little from those in air. Within the limitations of the computational method, the results presented are sufficiently encouraging to warrant further experiments.
    Keywords: AERODYNAMICS
    Type: NASA-TP-3496 , L-17401 , NAS 1.60:3496
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 85
    facet.materialart.
    Unknown
    Application of Pressure Sensitive Paint in Hypersonic Flows (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: It is well known in the aerodynamic field that pressure distribution measurement over the surface of an aircraft model is a problem in experimental aerodynamics. For one thing, a continuous pressure map can not be obtained with the current experimental methods since they are discrete. Therefore, interpolation or CFD methods must be used for a more complete picture of the phenomenon under study. For this study, a new technique was investigated which would provide a continuous pressure distribution over the surface under consideration. The new method is pressure sensitive paint. When pressure sensitive paint is applied to an aerodynamic surface and placed in an operating wind-tunnel under appropriate lighting, the molecules luminesce as a function of the local pressure of oxygen over the surface of interest during aerodynamic flow. The resulting image will be brightest in the areas of low pressure (low oxygen concentration), and less intense in the areas of high pressure (where oxygen is most abundant on the surface). The objective of this investigation was to use pressure sensitive paint samples from McDonnell Douglas (MDD) for calibration purpose in order to assess the response of the paint under appropriate lighting and to use the samples over a flat plate/conical fin mounted at 75 degrees from the center of the plate in order to study the shock/boundary layer interaction at Mach 6 in the Von Karman wind-tunnel. From the result obtained it was concluded that temperature significantly affects the response of the paint and should be given the uppermost attention in the case of hypersonic flows. Also, it was found that past a certain temperature threshold, the paint intensity degradation became irreversible. The comparison between the pressure tap measurement and the pressure sensitive paint showed the right trend. However, there exists a shift when it comes to the actual value. Therefore, further investigation is under way to find the cause of the shift.
    Keywords: AERODYNAMICS
    Type: NASA-TM-106824 , E-9373 , NAS 1.15:106824
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 86
    facet.materialart.
    Unknown
    High Pressure Earth Storable Rocket Technology Program: Basic Program (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The HIPES Program was conducted for NASA-LeRC by TRW. The Basic Program consisted of system studies, design of testbed engine, fabrication and testing of engine. Studies of both pressure-fed and pump-fed systems were investigated for N2O4 and both MMH and N2H4 fuels with the result that N2H4 provides the maximum payload for all satellites over MMH. The higher pressure engine offers improved performance with smaller envelope and associated weight savings. Pump-fed systems offer maximum payload for large and medium weight satellites while pressure-fed systems offer maximum payload for small light weight satellites. The major benefits of HIPES are high performance within a confined length maximizing payload for lightsats which are length (volume) constrained. Three types of thrust chambers were evaluated -- Copper heatsink at 400, 500 and 600 psia chamber pressures for performance/thermal; water cooled to determine heat absorbed to predict rhenium engine operation; and rhenium to validate the concept. The HIPES engine demonstrated very high performance at 50 lbf thrust (epsilon = 150) and Pc = 500 psia with both fuels: Isp = 337 sec using N2O4-N2H4 and ISP = 327.5 sec using N2O4-MMH indicating combustion efficiencies greater than 98%. A powder metallurgy rhenium engine demonstrated operation with high performance at Pc = 500 psia which indicated the viability of the concept.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-195449 , E-9514 , NAS 1.26:195449
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 87
    facet.materialart.
    Unknown
    Airfoil modification effects on subsonic and transonic pressure distributions and performance for the EA-6B airplane (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Longitudinal characteristics and wing-section pressure distributions are compared for the EA-6B airplane with and without airfoil modifications. The airfoil modifications were designed to increase low-speed maximum lift for maneuvering, while having a minimal effect on transonic performance. Section contour changes were confined to the leading-edge slat and trailing-edge flap regions of the wing. Experimental data are analyzed from tests in the Langley 16-Foot Transonic Tunnel on the baseline and two modified wing-fuselage configurations with the slats and flaps in their retracted positions. Wing modification effects on subsonic and transonic performance are seen in wing-section pressure distributions of the various configurations at similar lift coefficients. The modified-wing configurations produced maximum lift coefficients which exceeded those of the baseline configuration at low-speed Mach numbers (0.300 and 0.400). This benefit was related to the behavior of the wing upper surface leading-edge suction peak and the behavior of the trailing-edge pressure. At transonic Mach numbers (0.725 to 0.900), the wing modifications produced a somewhat stronger nose-down pitching moment, a slightly higher drag at low-lift levels, and a lower drag at higher lift levels.
    Keywords: AERODYNAMICS
    Type: NASA-TP-3516 , L-17360 , NAS 1.60:3516
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 88
    facet.materialart.
    Unknown
    Aerodynamics model for a generic ASTOVL lift-fan aircraft (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report describes the aerodynamics model used in a simulation model of an advanced short takeoff and vertical landing (ASTOVL) lift-fan fighter aircraft. The simulation model was developed for use in piloted evaluations of transition and hover flight regimes, so that only low speed (M approximately 0.2) aerodynamics are included in the mathematical model. The aerodynamic model includes the power-off aerodynamic forces and moments and the propulsion system induced aerodynamic effects, including ground effects. The power-off aerodynamics data were generated using the U.S. Air Force Stability and Control Digital DATCOM program and a NASA Ames in-house graphics program called VORVIEW which allows the user to easily analyze arbitrary conceptual aircraft configurations using the VORLAX program. The jet-induced data were generated using the prediction methods of R. E. Kuhn et al., as referenced in this report.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110347 , A-950051 , NAS 1.15:110347
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 89
    facet.materialart.
    Unknown
    Flow visualization studies of VTOL aircraft models during Hover in ground effect (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A flow visualization study of several configurations of a jet-powered vertical takeoff and landing (VTOL) aircraft model during hover in ground effect was conducted. A surface oil flow technique was used to observe the flow patterns on the lower surfaces of the model. There were significant configuration effects. Wing height with respect to fuselage, the presence of an engine inlet duct beside the fuselage, and nozzle pressure ratio are seen to have strong effects on the surface flow angles on the lower surface of the wing. This test was part of a program to improve the methods for predicting the hot gas ingestion (HGI) for jet-powered vertical/short takeoff and landing (V/STOL) aircraft. The tests were performed at the Jet Calibration and Hover Test (JCAHT) Facility at Ames Research Center.
    Keywords: AERODYNAMICS
    Type: NASA-TM-108860 , A-95025 , NAS 1.15:108860
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 90
    facet.materialart.
    Unknown
    Study of potential aerodynamic benefits from spanwise blowing at wingtip (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Comprehensive experimental and analytical studies have been conducted to assess the potential aerodynamic benefits from spanwise blowing at the tip of a moderate-aspect-ratio swept wing. Previous studies on low-aspect-ratio wings indicated that blowing from the wingtip can diffuse the tip vortex and displace it outward. The diffused and displaced vortex will induce a smaller downwash at the wing, and consequently the wing will have increased lift and decreased induced drag at a given angle of attack. Results from the present investigation indicated that blowing from jets with a short chord had little effect on lift or drag, but blowing from jets with a longer chord increased lift near the tip and reduced drag at low Mach numbers. A Navier-Stokes solver with modified boundary conditions at the tip was used to extrapolate the results to a Mach number of 0.72. Calculations indicated that lift and drag increase with increasing jet momentum coefficient. Because the momentum of the jet is typically greater than the reduction in the wing drag and the increase in the wing lift due to spanwise blowing is small, spanwise blowing at the wingtip does not appear to be a practical means of improving the aerodynamic efficiency of moderate-aspectratio swept wings at high subsonic Mach numbers.
    Keywords: AERODYNAMICS
    Type: NASA-TP-3515 , L-17368 , NAS 1.60:3515
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 91
    facet.materialart.
    Unknown
    Flow structure generated by perpendicular blade vortex interaction and implications for helicopter noise predictions (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This report summarizes accomplishments and progress for the period ending April 1995. Much of the work during this period has concentrated on preparation for an analysis of data produced by an extensive wind tunnel test. Time has also been spent further developing an empirical theory to account for the effects of blade-vortex interaction upon the circulation distribution of the vortex and on preliminary measurements aimed at controlling the vortex core size.
    Keywords: AERODYNAMICS
    Type: NASA-CR-198590 , NAS 1.26:198590
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 92
    facet.materialart.
    Unknown
    Horizontal axis wind turbine post stall airfoil characteristics synthesization (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Blade-element/momentum performance prediction codes are routinely used for wind turbine design and analysis. A weakness of these codes is their inability to consistently predict peak power upon which the machine structural design and cost are strongly dependent. The purpose of this study was to compare post-stall airfoil characteristics synthesization theory to a systematically acquired wind tunnel data set in which the effects of aspect ratio, airfoil thickness, and Reynolds number were investigated. The results of this comparison identified discrepancies between current theory and the wind tunnel data which could not be resolved. Other factors not previously investigated may account for these discrepancies and have a significant effect on peak power prediction.
    Keywords: AERODYNAMICS
    Type: DASCON Engineering, Collected Papers on Wind Turbine Technology; p 35-39
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 93
    facet.materialart.
    Unknown
    Comparison of Numerical Results and Multicavity Purge and Rim Seal Data with Extensions to Dynamics (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The computation of flows within interconnected, multiple-disk cavities shows strong interaction between the cavities and the power stream. For this reason, simulations of single cavities in such cases are not realistic; the complete, linked configuration must be considered. Unsteady flow fields affect engine stability and can engender power-stream-driven secondary flows that produce local hot spotting or general cavity heating. Further, a concentric whirling rotor produces a circumferential pressure wave, but a statically eccentric whirling rotor produces a radial wave; both waves affect cavity ingestion and the stability of the entire engine. It is strongly suggested that seals be used to enhance turbojet engine stability. Simple devices, such as swirl brakes, honeycomb inserts, and new seal configurations, should be considered. The cost effectiveness of the NASA Lewis Research Center seals program can be expressed in terms of program goals (e.g., the Integrated High-pressure/Temperature Engine Technology (IHPTET) cannot be achieved without such a program), cost (savings to $250 million/1-percent decrease in specific fuel consumption), and indirect benefits (reduction of atmospheric NO(x) and CO2 and reduction of powerplant downtime).
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TM-106685 , E-9039 , NAS 1.15:106685 , Northern Ohio Technical Symposium, Aerospace Today; Cleveland, OH; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 94
    facet.materialart.
    Unknown
    Effects of thermal and electrical stressing on the breakdown behavior of space wiring (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Several failures in the electrical wiring systems of many aircraft and space vehicles have been attributed to arc tracking and damaged insulation. In some instances, these failures proved to be very costly as they have led to the loss of many aircraft and imperilment of space missions. Efforts are currently underway to develop lightweight, reliable, and arc track resistant wiring for aerospace applications. In this work, six wiring constructions were evaluated in terms of their breakdown behavior as a function of temperature. These hybrid constructions employed insulation consisting of Kapton, Teflon, and cross-linked Tefzel. The properties investigated included the 400 Hz AC dielectric strength at ambient and 200 C, and the lifetime at high temperature with an applied bias of 40, 60, and 80% of breakdown voltage level. The results obtained are discussed, and conclusions are made concerning the suitability of the wiring constructions investigated for aerospace applications.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-CR-198360 , E-9750 , NAS 1.26:198360
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 95
    facet.materialart.
    Unknown
    Flight test evaluation of the Stanford University/United Airlines differential GPS Category 3 automatic landing system (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Test flights were conducted to evaluate the capability of Differential Global Positioning System (DGPS) to provide the accuracy and integrity required for International Civil Aviation Organization (ICAO) Category (CAT) 3 precision approach and landings. These test flights were part of a Federal Aviation Administration (FAA) program to evaluate the technical feasibility of using DGPS based technology for CAT 3 precision approach and landing applications. A United Airlines Boeing 737-300 (N304UA) was equipped with DGPS receiving equipment and additional computing capability provided by Stanford University. The test flights were conducted at NASA Ames Research Center's Crows Landing Flight Facility, Crows Landing, California. The flight test evaluation was based on completing 100 approaches and autolandings; 90 touch and go, and 10 terminating with a full stop. Two types of accuracy requirements were evaluated: 1) Total system error, based on the Required Navigation Performance (RNP), and 2) Navigation sensor error, based on ICAO requirements for the Microwave Landing System (MLS). All of the approaches and autolandings were evaluated against ground truth reference data provided by a laser tracker. Analysis of these approaches and autolandings shows that the Stanford University/United Airlines system met the requirements for a successful approach and autolanding 98 out of 100 approaches and autolandings, based on the total system error requirements as specified in the FAA CAT 3 Level 2 Flight Test Plan.
    Keywords: AERODYNAMICS
    Type: NASA-TM-110354 , A-950066 , NAS 1.15:110354
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 96
    facet.materialart.
    Unknown
    Transonic aerodynamic characteristics of a proposed wing-body reusable launch vehicle concept (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A proposed wing-body reusable launch vehicle was tested in the NASA Marshall Space Flight Center's 14 x 14-inch trisonic wind tunnel during the winter of 1994. This test resulted in the vehicle's subsonic and transonic, Mach 0.3 to 1.96, longitudinal and lateral aerodynamic characteristics. The effects of control surface deflections on the basic vehicle's aerodynamics, including a body flap, elevons, ailerons, and tip fins, are presented.
    Keywords: AERODYNAMICS
    Type: NASA-TM-108489 , NAS 1.15:108489
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 97
    facet.materialart.
    Unknown
    Development of a linearized unsteady Euler analysis for turbomachinery blade rows (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A linearized unsteady aerodynamic analysis for axial-flow turbomachinery blading is described in this report. The linearization is based on the Euler equations of fluid motion and is motivated by the need for an efficient aerodynamic analysis that can be used in predicting the aeroelastic and aeroacoustic responses of blade rows. The field equations and surface conditions required for inviscid, nonlinear and linearized, unsteady aerodynamic analyses of three-dimensional flow through a single, blade row operating within a cylindrical duct, are derived. An existing numerical algorithm for determining time-accurate solutions of the nonlinear unsteady flow problem is described, and a numerical model, based upon this nonlinear flow solver, is formulated for the first-harmonic linear unsteady problem. The linearized aerodynamic and numerical models have been implemented into a first-harmonic unsteady flow code, called LINFLUX. At present this code applies only to two-dimensional flows, but an extension to three-dimensions is planned as future work. The three-dimensional aerodynamic and numerical formulations are described in this report. Numerical results for two-dimensional unsteady cascade flows, excited by prescribed blade motions and prescribed aerodynamic disturbances at inlet and exit, are also provided to illustrate the present capabilities of the LINFLUX analysis.
    Keywords: AERODYNAMICS
    Type: NASA-CR-4677 , E-9575 , NAS 1.26:4677 , R95-970293
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 98
    facet.materialart.
    Unknown
    High frequency flow-structural interaction in dense subsonic fluids (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Prediction of the detailed dynamic behavior in rocket propellant feed systems and engines and other such high-energy fluid systems requires precise analysis to assure structural performance. Designs sometimes require placement of bluff bodies in a flow passage. Additionally, there are flexibilities in ducts, liners, and piping systems. A design handbook and interactive data base have been developed for assessing flow/structural interactions to be used as a tool in design and development, to evaluate applicable geometries before problems develop, or to eliminate or minimize problems with existing hardware. This is a compilation of analytical/empirical data and techniques to evaluate detailed dynamic characteristics of both the fluid and structures. These techniques have direct applicability to rocket engine internal flow passages, hot gas drive systems, and vehicle propellant feed systems. Organization of the handbook is by basic geometries for estimating Strouhal numbers, added mass effects, mode shapes for various end constraints, critical onset flow conditions, and possible structural response amplitudes. Emphasis is on dense fluids and high structural loading potential for fatigue at low subsonic flow speeds where high-frequency excitations are possible. Avoidance and corrective measure illustrations are presented together with analytical curve fits for predictions compiled from a comprehensive data base.
    Keywords: AERODYNAMICS
    Type: NASA-CR-4652 , M-773 , NAS 1.26:4652
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 99
    facet.materialart.
    Unknown
    Developmental problems and their solution for the Space Shuttle main engine alternate liquid oxygen high-pressure turbopump: Anomaly or failure investigation the key (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Space Shuttle main engine (SSME) alternate high-pressure liquid oxygen pump experienced synchronous vibration and ball bearing life problems that were program threatening. The success of the program hinged on the ability to solve these development problems. The design and solutions to these problems are engirded in the lessons learned and experiences from prior programs, technology programs, and the ability to properly conduct failure or anomaly investigations. The failure investigation determines the problem cause and is the basis for recommending design solutions. For a complex problem, a comprehensive solution requires that formal investigation procedures be used, including fault trees, resolution logic, and action items worked through a concurrent engineering-multidiscipline team. The normal tendency to use an intuitive, cut-and-try approach will usually prove to be costly, both in money and time and will reach a less than optimum, poorly understood answer. The SSME alternate high-pressure oxidizer turbopump development has had two complex problems critical to program success: (1) high synchronous vibrations and (2) excessive ball bearing wear. This paper will use these two problems as examples of this formal failure investigation approach. The results of the team's investigation provides insight into the complexity of the turbomachinery technical discipline interacting/sensitivities and the fine balance of competing investigations required to solve problems and guarantee program success. It is very important to the solution process that maximum use be made of the resources that both the contractor and Government can bring to the problem in a supporting and noncompeting way. There is no place for the not-invented-here attitude. The resources include, but are not limited to: (1) specially skilled professionals; (2) supporting technologies; (3) computational codes and capabilities; and (4) test and manufacturing facilities.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: NASA-TP-3553 , M-780 , NAS 1.60:3553
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 100
    facet.materialart.
    Unknown
    Measurements of store forces and moments and cavity pressures for a generic store in and near a box cavity at subsonic and transonic speeds (1995)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An experimental force and moment study was conducted in the Langley 8-Foot Transonic Pressure Tunnel for a generic store in and near rectangular box cavities contained in a flat-plate configuration at subsonic and transonic speeds. Surface pressures were measured inside the cavities and on the flat plate. The length-to-height ratios were 5.42, 6.25, 10.83, and 12.50. The corresponding width-to-height ratios were 2.00, 2.00, 4.00, and 4.00. The free-stream Mach number range was from 0.20 to 0.95. Surface pressure measurements inside the cavities indicated that the flow fields for the shallow cavities were either closed or transitional near the transitional/closed boundary. For the deep cavities, the flow fields were either open or near the open/transitional boundary. The presence of the store did not change the type of flow field and had only small effects on the pressure distributions. For transitional or open transitional flow fields, increasing the free-stream Mach number resulted in large reductions in pitching-moment coefficient. Values of pitching-moment coefficient were always much greater for closed flow fields than for open flow fields.
    Keywords: AERODYNAMICS
    Type: NASA-TM-4611 , L-17388 , NAS 1.15:4611
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...