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  • AERODYNAMICS  (3,347)
  • 1980-1984  (2,091)
  • 1970-1974  (1,256)
  • 101
    Publication Date: 2011-08-16
    Description: Windward injection into supersonic stream at angle of attack, minimizing vortex disruption
    Keywords: AERODYNAMICS
    Type: ; 394-398. (
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  • 102
    Publication Date: 2011-08-16
    Description: Viscous slipstream flow downstream of triple shock wave intersection in supersonic diffuser air flow, using Pitot and static pressure probe measurements
    Keywords: AERODYNAMICS
    Type: ; - ASTRONOMY 1969- TE
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  • 103
    Publication Date: 2011-08-16
    Description: Retrorocket jet size and structure for scientific instruments soft Mars landing, estimating off- optimum supersonic jet interaction with quiescent atmosphere
    Keywords: AERODYNAMICS
    Type: ; STITUTION OF ENGINEE
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  • 104
    Publication Date: 2011-08-16
    Description: Scaling relations showing effects of ballistic coefficient, flight path angle and inverse atmospheric scale height on heating of ballistic entry bodies
    Keywords: AERODYNAMICS
    Type: ; STITUTION OF ENGINEE
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  • 105
    Publication Date: 2011-08-16
    Description: The wave interference effects for bodies or wings in a mirror-symmetric arrangement, and in an antisymmetric arrangement are discussed. It is shown that while in the case of a mirror-symmetric arrangement large adverse interference effects can be observed, antisymmetric arrangements provide comparatively much smaller wave drags. The single continuous wing panels also adapt themselves more readily to varying angles of obliquity, and hence, to varying flight speeds. A detailed review is presented of the previous work on the aerodynamic properties and flight stability of oblique elliptic wing combinations. A possible mode of application of these combinations to transport aircraft operating at moderate supersonic speeds is suggested.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Feb. 197
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  • 106
    Publication Date: 2011-08-16
    Description: The experiment was performed on the test section sidewall in a supersonic pressure tunnel. The boundary layer at the test station was surveyed in turn by each of 8 impact probes ranging in size from about 1.3 to 48 mm. The impact pressures measured by these probes were combined with the test section static pressure to calculate Mach numbers. Probe displacement effects were evaluated in terms of these Mach number values.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Apr. 197
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  • 107
    Publication Date: 2011-08-16
    Description: Features of hypersonic, finite-span separated flows with a turbulent boundary layer have been studied to provide a partial assessment of transverse outflow effects on separated flowfield characteristics. Results demonstrate the critical importance of transverse outflow in determining some of the characteristic features of a turbulent, separated boundary layer.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Apr. 197
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  • 108
    Publication Date: 2011-08-16
    Description: Results of aerodynamic balance and pressure measurements carried out in a hypersonic gun tunnel (at a free-stream Mach number of 8.2 and a Reynolds number of 800,000) on delta wings having sharp leading edges swept at 70 and 76 deg. The experimental force and pressure coefficients and shock angles are discussed in relation to simple prediction methods. Some transition data are also included.
    Keywords: AERODYNAMICS
    Type: Aeronautical Society of India; vol. 23
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  • 109
    Publication Date: 2011-08-16
    Description: Modified asymptotic perturbation expansion method application to free flow rotation effect on boundary layer for hypersonic flow about blunt body
    Keywords: AERODYNAMICS
    Type: ; 35 (
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  • 110
    Publication Date: 2011-08-16
    Description: Axisymmetric inlet design for turboramjet powered hypersonic cruise vehicle, examining effects of spillage and cowl drags on air flow characteristics
    Keywords: AERODYNAMICS
    Type: ; UG REVUE(
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  • 111
    Publication Date: 2011-08-16
    Description: Small curvature radius/throat radius ratio supersonic nozzles mass flow rate coefficients at high Reynolds numbers, appraising isentropic flow prediction methods
    Keywords: AERODYNAMICS
    Type: ; VUE SCIENTIFIQUE ET
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  • 112
    Publication Date: 2011-08-16
    Description: Maximum stagnation temperature on swept wing leading edge for equilibrium glide entry of space shuttle
    Keywords: AERODYNAMICS
    Type: ; 63 (
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  • 113
    Publication Date: 2011-08-16
    Description: Wind tunnel apparatus for reproducing coning and spinning motions of bodies of revolution, using six-component strain gage balance for aerodynamic forces
    Keywords: AERODYNAMICS
    Type: ; UGREVUE(
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  • 114
    Publication Date: 2011-08-16
    Description: Shock tunnel drag measurements on sharp slender cones in near free molecule hypersonic flow in air and He
    Keywords: AERODYNAMICS
    Type: ; YAL SOCIETY (
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  • 115
    Publication Date: 2011-08-16
    Description: Vortex-induced heating alleviation to lee side of slender wings in hypersonic flow by contouring leading edge planform
    Keywords: AERODYNAMICS
    Type: ; YAL SOCIETY (
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  • 116
    Publication Date: 2011-08-16
    Description: Hypersonic theoretical/experimental correlations of aerodynamic characteristics for space shuttle design
    Keywords: AERODYNAMICS
    Type: NASA, WASHINGTON NASA SPACE SHUTTLE TECHNOL. CONF., VOL. 1 APR. 1971; P 455-492
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  • 117
    Publication Date: 2011-08-16
    Description: Reynolds number simulation requirements for subsonic wind tunnel tests of space shuttle configurations
    Keywords: AERODYNAMICS
    Type: NASA, WASHINGTON NASA SPACE SHUTTLE TECHNOL. CONF., VOL. 1 APR. 1971; P 423-453
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  • 118
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    Publication Date: 2011-08-16
    Description: Heat transfer and shock wave shapes about blunt slender cones in viscous-inviscid coupling hypersonic flow
    Keywords: AERODYNAMICS
    Type: ; UGREVUE(
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  • 119
    Publication Date: 2011-08-16
    Description: Heat transfer from turbulent boundary layer interacting with shock and expansion waves in supersonic flow
    Keywords: AERODYNAMICS
    Type: ; UGREVUE(
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  • 120
    Publication Date: 2011-08-16
    Description: Spheres drag coefficient at hypersonic Mach numbers for near free molecular flow
    Keywords: AERODYNAMICS
    Type: ; UGREVUE(
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  • 121
    Publication Date: 2011-08-16
    Description: Aerodynamic characteristics of delta wing space shuttle configurations
    Keywords: AERODYNAMICS
    Type: NASA SPACE SHUTTLE TECHNOL. CONF., VOL. 1 APR. 1971; P 311-373
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  • 122
    Publication Date: 2011-08-16
    Description: Forces on two dimensional oscillating airfoil in subsonic compressible wind tunnel flow, solving partial differential equation for pressure potential by integral transform technique
    Keywords: AERODYNAMICS
    Type: ; YAL SOCIETY (
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  • 123
    Publication Date: 2011-08-16
    Description: An unsteady lifting-surface theory is developed for the calculation of the airload on a semi-infinite-span thin wing in a compressible flow due to interaction with an oblique gust. By using the solutions obtained for a two-dimensional wing, the problem is formulated so that the unknown is taken to be the difference between the airload on the semi-infinite wing and that on a two-dimensional wing under the same gust conditions. Since this airload difference is nonzero only near the wing tip, the control points need be distributed in the tip region only; this significantly simplifies the numerical procedure. Results are presented for a wing with rectangular tip. The implication for noise and unsteady loads due to blade-vortex interaction for helicopter rotors is discussed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Dec. 197
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  • 124
    Publication Date: 2011-08-16
    Description: Limitations concerning the possibility to simulate all the significant flow and thermal phenomena occurring during the entry of a space vehicle into a planetary atmosphere make it necessary to rely on computational analyses to obtain the required data for the design of the spacecraft needed for the NASA missions planned for the next two decades. 'Benchmark' computer programs concerned with complete, detailed, and accurate computational solutions of entry problems are considered along with programs representing engineering approximations for cases in which the accuracy provided by the benchmark programs is not needed. The information obtainable by computational analysis has to be supplemented by actual flight experience in order to meet the goals of the NASA entry-technology program. The individual space missions planned for the coming years are examined together with the possibilities for obtaining the data needed to satisfy the entry requirements in each case.
    Keywords: AERODYNAMICS
    Type: Astronautics and Aeronautics; 12; Dec. 197
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  • 125
    Publication Date: 2011-08-16
    Description: The analysis of sound fields from arbitrary source distributions in terms of Legendre and spherical Hankel functions is well known. The purpose of this paper is to extend this classical method of analysis to environments such as jet flows where flow and flow gradients are inherently present. The wave-equation governing the radiation of sound in such an environment is derived. The steady state flow and flow gradients in the axial and transverse directions appear as coefficients in the terms of the wave-equation. A semi-numerical method is used to solve the wave-equation in terms of modified spherical harmonics yielding the phase velocities and the directivities of an infinite set of modes. The directivity of each mode is obtained in terms of modified Legendre functions by numerical integration. Some results of these directivity and phase-velocity calculations are presented for a limited number of frequency and flow parameters. Both convective and shear refraction are shown to be important.
    Keywords: AERODYNAMICS
    Type: Journal of Sound and Vibration; 36; Sept. 8
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  • 126
    Publication Date: 2011-08-16
    Description: A general equation governing aerodynamic sound generation in the presence of solid boundaries is derived. It is shown that all the theories in the literature appear as special cases of this general equation. Derived special equations for propeller and fan noise are likewise shown to be more general than the conventional equations in that they make allowance for variation in retarded time over the blade surfaces.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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  • 127
    Publication Date: 2011-08-16
    Description: A method for automatic numerical generation of a general curvilinear coordinate system with coordinate lines coincident with all boundaries of a general multi-connected region containing any number of arbitrarily shaped bodies is presented. With this procedure the numerical solution of a partial differential system may be done on a fixed rectangular field with a square mesh with no interpolation required regardless of the shape of the physical boundaries, regardless of the spacing of the curvilinear coordinate lines in the physical field, and regardless of the movement of the coordinate system. Numerical solutions for the lifting and nonlifting potential flow about Joukowski and Karman-Trefftz airfoils using this coordinate system generation show excellent comparison with the analytic solutions. The application to fields with multiple bodies is illustrated by a potential flow solution for multiple airfoils.
    Keywords: AERODYNAMICS
    Type: Journal of Computational Physics; 15; July 197
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  • 128
    Publication Date: 2011-08-16
    Description: The propagation of waves of acoustic frequencies in curved ducts of rectangular cross section is studied for the first four modes. The analysis makes use of Bessel functions of the order (n + 1/2) to construct curves of wavenumber in the duct versus imposed wavenumber and to determine the profile of vibrational velocities. A wide range of duct widths and unrestricted radii of curvature have been considered. The characteristics of motion in a bend are compared with propagation of waves in a straight duct, and important differences in the behavior of waves are noted.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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  • 129
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    Publication Date: 2011-08-16
    Description: A scanning laser Doppler velocimeter was used to measure the axial velocity defect in the cores of trailing vortices behind a lifting airfoil of rectangular planform. Data were obtained at several different angles of attack and downstream distances ranging from 30 to 1000 chord lengths. The test was designed to obtain continuous data from the near field into the far field while removing uncertainties associated with the interpretation of data obtained by the hydrogen bubble technique. The measured velocities of V sub x/U sub infinity are compared with those predicted. The agreement is remarkably good over the entire range of downstream distances, which supports the credibility of calculating axial velocities using the results of Moore and Saffman (1973).
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Aug. 197
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  • 130
    Publication Date: 2011-08-16
    Description: A backscatter laser Doppler velocimeter which simultaneously senses the axial and the tangential components of the velocity has been used to measure the velocity distributions in the near wake of a swept wing semispan transport model in a wind tunnel. The model configuration included nacelles, pylons, antishock bodies, and wing flaps which could be deflected 27 deg. Typical wake vortex velocity profiles are presented for the flaps-retracted and the flaps-deployed 27 deg configurations, respectively.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; June 197
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  • 131
    Publication Date: 2011-08-16
    Description: A primary factor governing hypersonic flowfield characteristics of blunt vehicles entering planetary atmospheres is the normal shock density ratio. Hence, a means of duplicating or simulating the high density ratios experienced during planetary entry is needed. One facility having the capability of generating a range of hypersonic-hypervelocity flow conditions in arbitrary test gases is the expansion tube. Preliminary shock shape results obtained in the Langley 6-in. expansion tube at hypersonic conditions are presented. Normal shock density ratios from approximately 4 to 19 were generated using helium, air, and CO2 test gases at freestream velocities from 5 to 7 km/sec. Test models were a flat-faced cylinder and the Viking aeroshell.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Mar. 197
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  • 132
    Publication Date: 2011-08-16
    Description: An investigation is conducted concerning the validity of analytical methods which are based on deriving an integral equation, taking into account small perturbations in the case of a nonuniform but irrotational flow. The results obtained apply to a wide Mach number range, but are restricted to small amplitude motions and to nonviscous flows. It is shown that the integral equation relating the unknown velocity potential to the known normal flow velocity can be derived from the appropriate Green's identity.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Dec. 197
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  • 133
    Publication Date: 2011-08-16
    Description: Approximate solution for position and strength of shock waves about cones in steady supersonic flow
    Keywords: AERODYNAMICS
    Type: ; ADEMIE DES SCIENCES
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  • 134
    Publication Date: 2011-08-16
    Description: A simple eddy-viscosity model is shown to make it possible to calculate numerically the mean properties of a turbulent wake. Although the structure of the Reynolds stress terms is not resolved, the results obtained are adequate for predicting velocity profiles and displacement thicknesses.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Feb. 197
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  • 135
    Publication Date: 2011-08-16
    Description: Description of additional results indicating that a unique relationship exists between rms sound pressure level and transition Reynolds number, provided all other parameters are held nearly invariant. The results illustrate the different levels of the transition Reynolds numbers obtained in six facilities with nearly invariant laminar boundary layers on the different models (at the same local unit Reynolds number) and indicate that some facility characteristic has a strong influence on the transition Reynolds numbers.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 9; Dec. 197
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  • 136
    Publication Date: 2011-08-16
    Description: The application of Rose's (1970) analytical method to the study of a shock wave interacting with a turbulent layer on a blunted compression surface is described. Only those details of the method that specifically apply to the case under consideration are discussed.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Apr. 197
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  • 137
    Publication Date: 2011-08-16
    Description: Some results are described for a lifting rectangular wing centrally located on a circular-cylindrical body. This simple configuration has been utilized in order to assess the merits of a mapping technique for wing-body configurations. The procedure employed makes use of a coordinate transformation to simplify specification of the surface boundary condition in the computation of the flow about the wing. The method can be extended to incorporate wing sweep, finite length body of noncircular cross section, and arbitrary wing placement; however, these extensions involve a considerable increase in complexity of the problem.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Apr. 197
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  • 138
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    Publication Date: 2011-08-16
    Description: A simple form is presented of the relationships derived by Betz for the inviscid, fully developed structure of lift-generated vortices behind aircraft. An extension is then made to arbitrary span-load distributions by inferring guidelines for the selection of rollup centers for the vortex sheet. These techniques are easier to use and yield more realistic estimates of the rolled-up structure of vortices than the original form of Betz' theory when the span loading differs appreciably from elliptic loading.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 10; Nov. 197
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  • 139
    Publication Date: 2011-08-16
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Dec. 197
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  • 140
    Publication Date: 2011-08-16
    Description: A model based on Lighthill's theory for predicting aerodynamic noise from a turbulent shear flow is developed. This model is a generalization of the one developed by Ribner. It does not require that the turbulent correlations factor into space and time-dependent parts. It replaces his assumption of isotropic turbulence by the more realistic one of axisymmetric turbulence. In the course of the analysis, a hierarchy of equations is developed wherein each succeeding equation involves more assumptions than the preceding equation but requires less experimental information for its use. The implications of the model for jet noise are discussed. It is shown that for the particular turbulence data considered anisotropy causes the high-frequency self-noise to be beamed downstream.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 54
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  • 141
    Publication Date: 2011-08-16
    Description: For the interaction of shock waves with turbulent boundary layers, obtained experimental three-dimensional separation results and correlations with earlier two-dimensional and three-dimensional data are presented. It is shown that separation occurs much earlier for turbulent three-dimensional than for two-dimensional flow at hypersonic speeds.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Nov. 197
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  • 142
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    Publication Date: 2011-08-16
    Description: A mathematical model of the vortex flow over a slender sharp-edged delta wing is proposed, and is shown to provide good agreement with the experiment. Although the technique requires experimental data in the form of the vortex core locations, it does account for the previously ignored mass entrainment of the vortex core.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Jan. 197
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  • 143
    Publication Date: 2011-08-16
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Nov. 197
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  • 144
    Publication Date: 2011-08-16
    Description: A modified, bidirectional shooting method is presented for solving boundary-layer equations under conditions of massive blowing. Unlike the conventional shooting method, which is unstable when the blowing rate increases, the proposed method avoids the unstable direction and is capable of solving complex boundary-layer problems involving mass and energy balance on the surface.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Nov. 197
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  • 145
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    Publication Date: 2011-08-16
    Description: The method of Fourier transforms is used to determine the kernel function which relates the pressure on a lifting surface to the prescribed downwash within the framework of Dowell's (1971) shear flow model. This model is intended to improve upon the potential flow aerodynamic model by allowing for the aerodynamic boundary layer effects neglected in the potential flow model. For simplicity, incompressible, steady flow is considered. The proposed method is illustrated by deriving known results from potential flow theory.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Nov. 197
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  • 146
    Publication Date: 2011-08-18
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 21; 809-815
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  • 147
    Publication Date: 2011-08-18
    Description: Previously cited in issue 5, p. 579, Accession no. A83-16536
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 22; 1094-110
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  • 148
    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2346, Accession no. A82-31959
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 22; 1139-114
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  • 149
    Publication Date: 2011-08-18
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 21; 700-707
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  • 150
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    Publication Date: 2011-08-18
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 21; 680-686
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  • 151
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    Publication Date: 2011-08-18
    Description: Laminar flow control is a technology with great potential for aircraft drag reduction. Stabilization of laminar boundary layers became known as natural laminar flow (NLF) and research led to the development of NLF airfoils. Research was also conducted on stabilization by suction, referred to as laminar flow control (LFC). Experiments demonstrated that extensive laminar flow could be achieved in flight. However, there remained doubts regarding the practicality of producing, with the technology then available, wing surfaces sufficiently smooth and wavefree to meet laminar-flow criteria and maintaining the wing surface quality in normal service. In 1976, the Aircraft Energy Efficiency (ACEE) program was begun by NASA to develop fuel-conservative technology for commercial transports. The progress of the ACEE program is discussed. Attention is given to LFC wing structures, and LFC leading-edge systems.
    Keywords: AERODYNAMICS
    Type: Aerospace America (ISSN 0740-722X); 22; 72-76
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  • 152
    Publication Date: 2011-08-18
    Description: Previously cited in issue 5, p. 586, Accession no. A83-16747
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4560); 21; 217-219
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  • 153
    Publication Date: 2011-08-19
    Description: Computations on zonal grids - in particular, grids with metric discontinuities resulting from the interspersion of highly clustered regions with coarse regions - are possible using a fully conservative form of the Osher upwind scheme. These zonal grids can result from an abrupt clustering of points near solution discontinuities or near other flow features that require improved resolution. The zonal approach is shown to capture shocks with almost 'shock-fitting' quality but with minimal effort. Results for inviscid flow, including quasi-one-dimensional nozzle flow, supersonic flow over a cylinder, and blast-wave diffraction by a ramp, are presented. These calculations demonstrate the powerful capabilities of the Osher scheme used in conjunction with zonal grids in simulating flow fields with complex shock patterns.
    Keywords: AERODYNAMICS
    Type: Computers and Fluids (ISSN 0045-7930); 12; 3, 19
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  • 154
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    Publication Date: 2011-08-18
    Description: The potential of planform modification and hinge-line relocation to improve the thrust efficiency of vortex flaps was experimentally investigated on a 60-deg cropped delta wing model. Spanwise segmentation of the flap, together with chord-tailoring of the segments, allowed the vortex to be maintained on the outboard flap surfaces to higher angles of attack. In addition, location of the flap hinge aft of and underneath the wing leading edge generated substantial thrust from the vortex suction acting on the leading-edge lower surface. A combination of these beneficial effects allowed the flap/wing area to be reduced from 11.4 percent of the continuous flap to 6.3 percent of segmented flap, essentially without detriment to the incremental lift-to-drag ratio due to flap addition in the lift coefficient range 0.5-0.7 based on the basic wing area.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 20; 1062-106
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  • 155
    Publication Date: 2011-08-18
    Description: Previously cited in issue 20, p. 3138, Accession no. A82-40893
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 20; 993-1006
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  • 156
    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 799, Accession no. A82-17876
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1611-161
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  • 157
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    Publication Date: 2011-08-18
    Description: A mesh system composed of multiple overset body-conforming grids is described for adapting finite-difference procedures to complex aircraft configurations. In this so-called 'chimera mesh,' a major grid is generated about a main component of the configuration and overset minor grids are used to resolve all other features. Methods for connecting overset multiple grids and modifications of flow-simulation algorithms are discussed. Computational tests in two dimensions indicate that the use of multiple overset grids can simplify the task of grid generation without an adverse effect on flow-field algorithms and computer code complexity.
    Keywords: AERODYNAMICS
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  • 158
    Publication Date: 2011-08-18
    Description: Previously cited in issue 17, p. 2873, Accession no. A81-38082
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1492-149
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  • 159
    Publication Date: 2011-08-19
    Description: A lifting surface theory was developed for a helicopter rotor in forward flight for compressible and incompressible flow. The method utilizes the concept of the linearized acceleration potential and makes use of the vortex lattice procedure. Calculations demonstrating the application of the method are given in terms of the lift distribution on a single rotor, a two-bladed rotor, and a rotor with swept-forward and swept-back tips. In addition, the lift on a rotor which is vibrating in a pitching mode at 4/rev is given. Compressibility effects and interference effects for a two-bladed rotor are discussed.
    Keywords: AERODYNAMICS
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  • 160
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 21; 528-533
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  • 161
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 22; 1748-175
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  • 162
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    Publication Date: 2011-08-16
    Description: Schlieren photographs of shock interference heating for space shuttles
    Keywords: AERODYNAMICS
    Type: NASA, WASHINGTON SPACE TRANSPORTATION SYSTEM TECHNOL. SYMP., VOL. 1 JUL. 1970; P 338-389
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  • 163
    Publication Date: 2011-08-16
    Description: Boundary layer transition on lifting reentry vehicles at high angles of attack
    Keywords: AERODYNAMICS
    Type: NASA, WASHINGTON SPACE TRANSPORTATION SYSTEM TECHNOL. SYMP., VOL. 1 JUL. 1970; P 445-462
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  • 164
    Publication Date: 2011-08-16
    Description: Wind tunnel tests of aerodynamic stability, boundary layer transition, and heat transfer in space shuttle orbiters
    Keywords: AERODYNAMICS
    Type: SPACE TRANSPORTATION SYSTEM TECHNOL. SYMP., VOL. 1 JUL. 1970; P 142-193
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  • 165
    Publication Date: 2011-08-16
    Description: Supersonic skin friction measurements in grit type boundary layer transition trips with zero heat transfer
    Keywords: AERODYNAMICS
    Type: ; SEARCH(
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  • 166
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    Publication Date: 2011-08-16
    Description: Radiation effects on viscous hypersonic low density stagnation flow using two layer model, calculating flow field and heat transfer coefficient
    Keywords: AERODYNAMICS
    Type: ; ACE(
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  • 167
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    Publication Date: 2011-08-16
    Description: Missile oscillations in plane during pitching moment hysteresis, discussing test coefficients suitability for predicting motion
    Keywords: AERODYNAMICS
    Type: ; RO(
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  • 168
    Publication Date: 2011-08-16
    Description: Off-centerline heating on lee surface of supersonic delta wing with separation and vortex initiation at leading edge
    Keywords: AERODYNAMICS
    Type: ; ADEMIE DES SCIENCES
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  • 169
    Publication Date: 2011-08-16
    Description: Adiabatic flow coefficient in supersonic nozzle with choked flow conducted over throat Reynolds number range
    Keywords: AERODYNAMICS
    Type: ; ADEMIE DES SCIENCES
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  • 170
    Publication Date: 2011-08-16
    Description: Electron concentration profiles in blunt nose vehicle shock layer during atmospheric near orbital entry at high altitudes, using finite rate chemistry
    Keywords: AERODYNAMICS
    Type: ; ADEMIE DES SCIENCES
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  • 171
    Publication Date: 2011-08-16
    Description: Results are presented of a procedure for estimating stability and control parameters from flight data, by using maximum likelihood methods employing an interactive computer system, which was established at the NASA Langley Research Center. Problems encountered are discussed.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 49-76
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  • 172
    Publication Date: 2011-08-16
    Description: A maximum likelihood estimator for a linear system with state and observation noise is developed to determine stability and control derivatives from flight data obtained in the presence of turbulence. The formulation for the longitudinal short-period mode is presented briefly, including a special case that greatly simplifies the problem if the measurement noise on one signal is negligible. The effectiveness and accuracy of the technique are assessed by applying it first to simulated flight data, in which the true parameter values and state noise are known, then to actual flight data obtained in turbulence. The results are compared with data obtained in smooth air and with wind-tunnel data. The complete maximum likelihood estimator, which accounts for both state and observation noise, is shown to give the most accurate estimate of the stability and control derivatives from flight data obtained in turbulence. It is superior to the techniques that ignores state noise and to the simplified method that neglects the measurement noise on the angle-of-attack signal.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 77-114
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  • 173
    Publication Date: 2011-08-16
    Description: Two methods for extracting stability derivatives from flight data are compared. A modified Newton-Raphson quasilinearization minimization technique and a digital-analog (hybrid) matching technique were used to analyze the same data maneuvers obtained from two aircraft. About 70 maneuvers from an F-111E aircraft were analyzed over a Mach number range of 0.3 to 2.0 and an angle of attack range of 3 to 19 degrees. About 20 maneuvers were analyzed for the X-24A lifting body at Mach numbers of 0.5, 0.8, and 0.9, and an angle of attack range of 4 to 13 degrees. Stability derivatives were extracted from these maneuvers and the results from the two techniques, along with wind tunnel results, were compared.
    Keywords: AERODYNAMICS
    Type: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 43-48
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  • 174
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    Publication Date: 2011-08-16
    Description: A pseudo-one-dimensional model of the supersonic combustion ramjet engine cycle is revised on the basis of recent (additional) data obtained from combustor tests. The data were generated in a simple nonreacting system which produces shock structures and shock/boundary layer interactions analogous to those observed at the entrance of supersonic combustors. It is shown that the revised model provides better descriptions of the wall pressure distributions and the overall shock pressure rises for the available test data.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 10; Sept
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  • 175
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    Publication Date: 2011-08-16
    Description: A transonic flow solution is presented for configurations with span-to-length ratios of order one. The angles of attack are sufficiently large to produce lift effects that are either dominant or comparable to the thickness effects. The analysis is performed with the aid of the method of matched asymptotic expansions. The results obtained are compared with data reported by Cheng and Hafez (1972).
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; May 1973
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  • 176
    Publication Date: 2011-08-16
    Description: Brief review of the operational principle and capability of the high-Reynolds-number wind tunnel developed over the last few years. Its test medium is stored in a Ludwieg tube and held there by means of a diaphragm. When the diaphragm is broken, a rearward-facing centered rarefaction fan propagates upstream through the test section and nozzle into the supply tube, and the useful run time is bounded by the reflected rarefaction wave and the starting shock wave caused by choking at the nozzle. The operating problems center around the ability of model and sting support systems to withstand the loads and to meet the instrumentation requirements. Evaluation tests have shown that satisfactory force and moment measurements can be obtained in this facility.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Mar. 197
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  • 177
    Publication Date: 2011-08-16
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 11; Feb. 197
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  • 178
    Publication Date: 2011-08-16
    Description: Direct skin friction measurements obtained on the wall of a Mach 19.8 nozzle are presented. These measurements of skin friction and values deduced from the profile data are compared with predictions from a finite difference theory and also with several 'flat-plate' prediction methods for skin friction.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Sept
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  • 179
    Publication Date: 2011-08-16
    Description: Investigation of the Taylor instability relative to the dynamical instability whose presence in the shock layer on a spacecraft entering the Jovian atmosphere is to be expected because of the difference in velocity across the shear layer. Presented calculations show that the Taylor instability at the interface between shock-heated freestream gas and ablation products is inconsequential in comparison to the shear layer instability.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Sept
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  • 180
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    Publication Date: 2011-08-16
    Description: The transition Reynolds number for shear layers produced by interactions between weak and strong shock waves is determined on the basis of experiments performed in a 20-in. (Mach 6) and an 11-in. (Mach 6.9) hypersonic tunnel. A variable angle wedge was used to generate a planar shock wave which interacted with the bow wave of a blunt body. An average value of the transition length (defined as the length along the shear layer from the shock interaction to the point where turbulence became visible on schlieren photographs) was used to determine the transition Reynolds number.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Aug. 197
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  • 181
    Publication Date: 2011-08-16
    Description: Correlations are given of measured pressure and heat-transfer peaks for shock/boundary-layer interactions and shear layer attachment on configurations with both two- and three-dimensional interactions. The peak values were obtained from an investigation of shock interference heating on hemispheres, a 30-deg included angle wedge, and a 2.54-cm-diam cylindrical leading-edge fin model. The investigation covers data for Mach numbers of 6 and 20 over freestream Reynolds numbers ranging from (3.3 to 25.6) million per meter, and specific heat ratios of 1.4 and 1.67.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Aug. 197
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  • 182
    Publication Date: 2011-08-16
    Description: Boundary-layer transition on 5- and 15-deg half-angle cones was studied as a function of angle of attack (ranging from 0 to 20 deg) in a 3.5 ft hypersonic wind tunnel at a freestream Mach number of 7.4. It is shown that the influence of the angle of attack on the transition Reynolds number is a function of the meridian angle. On the windward ray of the 15-deg cone, transition Reynolds numbers show an initial slight increase and then a decrease with increasing angle of attack; leeward-ray Reynolds numbers for this cone decrease rapidly with angle of attack. Windward-ray transition Reynolds numbers increase monotonically with angle of attack on the 5-deg cone, but the effect of the angle of attack on the leeward ray is the same as for the 15-deg cone.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Aug. 197
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  • 183
    Publication Date: 2011-08-16
    Description: The results of Murman and Krupp (1971) are used to develop a procedure for computing a transonic flow about a finite lifting wing. A small disturbance equation describing the velocity potential of three-dimensional wings is solved in the process. The procedure is applied to a wing with a symmetric biconvex airfoil section in a zero-incidence subsonic flow, to a supersonic rectangular lifting wing with a sharp leading edge and to a subcritical nonlifting rectangular wing with a blunt leading edge.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; July 197
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  • 184
    Publication Date: 2011-08-16
    Description: The inverse technique is used to obtain a mathematically and physically consistent solution of the flowfield in a nozzle from the mass generation surface through the supersonic region. The inverse method employs an assumed centerline function which is of the Cauchy type in that the values and the derivatives of the function are known. Since the Cauchy boundary conditions can give rise to numerical instabilities, the governing gasdynamic equations for rotational steady flow were transformed into a form which puts the geometry into a rectangular shape, and which spaces the network of interior points more finely in regions of the greatest gradients of the dependent variables. For arbitrarily specified centerline data, the solution of the governing flow equations may not exist, and if it does it may not depend continuously on the data.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; June 197
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  • 185
    Publication Date: 2011-08-16
    Description: Wall static pressure measurements and performance parameters are presented for axisymmetric supersonic nozzles with relatively steep convergent sections and comparatively small radius-of-curvature throats. The nozzle walls were essentially adiabatic. These results are compared with those obtained in other nozzles tested previously to appraise the influence of contraction shape on performance. Both the flow coefficient and the thrust were less than the corresponding values for one-dimensional, isentropic, plane flow for both the axial and radial inflow nozzles considered, but the specific impulse, the most important performance parameter, was found to be relatively unchanged. The thrust decrement for the axial inflow nozzles was established primarily by the shape of the contraction section, and could be estimated reasonably well from a conical sink flow consideration. The radial inflow nozzle has a potential advantage from a cooling point of view if used in a rocket engine.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; June 197
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  • 186
    Publication Date: 2011-08-16
    Description: Experimental results suggest that the boundary-layer mean profiles in hypersonic flows may be highly transitional in the outer part of the boundary layer before the transition process is detected at the surface. Means of determining the initial location where the transition process begins in the outer part of the boundary layer are considered.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; May 1972
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  • 187
    Publication Date: 2011-08-16
    Description: A first-order theory of the fluctuating lift and drag coefficients associated with the aerodynamically induced motions of rising and falling spherical wind sensors is developed. The equations of motion of a sensor are perturbed about an equilibrium state in which the buoyancy force balances the mean vertical drag force. It is shown that, to within first order in perturbation quantities, the aerodynamic lift force is confined to the horizontal, and the fluctuating drag force associated with fluctuations in the drag coefficient acts along the vertical. The perturbation equations are transformed with Fourier-Stieltjes integrals. The resulting equations lead to relationships between the power spectra of the aerodynamically induced velocity components and the spectra of the fluctuating lift and drag coefficients.
    Keywords: AERODYNAMICS
    Type: Journal of Applied Meteorology; 11; Apr. 197
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  • 188
    Publication Date: 2011-08-16
    Description: Description of a correlation, derived from water tank measurements in the wake of wings towed under water, that makes it possible to predict the downstream distance behind an aircraft in flight where its trailing vortex will begin to decay. Comparisons of measured and predicted data are discussed.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Nov. 197
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  • 189
    Publication Date: 2011-08-16
    Description: The artificial viscosity method of Kuwahara and Takami (1973) is used to calculate the roll-up of trailing vortices behind a number of practical aerodynamic configurations. Where possible, the results are compared for core location with available experimental data.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; Nov. 197
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  • 190
    Publication Date: 2011-08-16
    Description: Electron density profiles which include the effect of an ablated sodium impurity were computed for the boundary layer on a blunt-nosed body re-entering the atmosphere at 7.62 km/sec. Profiles are computed from the nose to a distance of four diameters along the RAM C-payload. A finite-difference, laminar, nonequilibrium chemistry boundary-layer program was used. Comparison of theory with S-band diagnostic antenna results, electron concentration deduced from X- and C-band attenuation data, and Langmuir probe data at several different aft body locations show that agreement is good at high altitude. At the lower altitudes there is disagreement between theory and S-band antenna data where the apparent discrepancy is attributed to the three-body recombination rate constant used for deionization of sodium coupled with the effect of angle of attack.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; June 197
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  • 191
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    Publication Date: 2011-08-16
    Description: The growth of the field of system identification is discussed along with changes in methodology which have taken place in recent years. The similarity between pattern recognition and system identification is pointed out, involving the modelling in the latter and the feature selection problem in the former. It is stated that once a model is formulated, including the disturbances and measurement errors, the parameter finding can be formulated as a statistical estimation problem. The various techniques and their application are discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Flight Res. Center Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 381-385
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  • 192
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    Publication Date: 2011-08-16
    Description: A state-of-the-arts review is given for the field of system identification. Progress in the field is traced from the early models of dynamic systems by Sir Isaac Newton up to the present day use of advanced techniques for numerous applications.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 375-379
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  • 193
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    Publication Date: 2011-08-16
    Description: The criterion that is proposed is an expected value of the mean square response error as an alternative to testing a model against new data. Modeling with respect to this new criterion does not change the estimate for a given model format from a maximum likelihood estimate or mean square response error estimate. The new criterion does, however, provide a means of comparing models with different formats and varying complexity. A numerical example is used to illustrate the application of the proposed criteria and the problem of searching for the best model. For all but the most trivial system identification problems, it is shown that a prohibitive number of combinations of terms of the model must be investigated to ensure the final model is best.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 291-313
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  • 194
    Publication Date: 2011-08-16
    Description: An error analysis program based on an output error estimation method was used to evaluate the effects of sensor and instrumentation errors on the estimation of aircraft stability and control derivatives. A Monte Carlo analysis was performed using simulated flight data for a high performance military aircraft, a large commercial transport, and a small general aviation aircraft for typical cruise flight conditions. The effects of varying the input sequence and combinations of the sensor and instrumentation errors were investigated. The results indicate that both the parameter accuracy and the corresponding measurement trajectory fit error can be significantly affected. Of the error sources considered, instrumentation lags and control measurement errors were found to be most significant.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 261-280
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  • 195
    Publication Date: 2011-08-16
    Description: The parameter identification scheme being used is a differential correction least squares procedure (Gauss-Newton method). The position, orientation, and derivatives of these quantities with respect to the parameters of interest (i.e., sensitivity coefficients) are determined by digital integration of the equations of motion and the parametric differential equations. The application of this technique to three vastly different sets of data is used to illustrate the versatility of the method and to indicate some of the problems that still remain.
    Keywords: AERODYNAMICS
    Type: Parameter Estimation Tech. and Appl. in Aircraft Flight Testing; p 191-195
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  • 196
    Publication Date: 2011-08-16
    Description: This paper presents a summary of principal results obtained from crossflow tests of a model 15-in.-diam lift fan installed in a wing in the NASA Lewis Research Center, 9 by 15 ft V/STOL Propulsion Wind Tunnel. Tests were run with and without exit louvers over a range of tunnel air speeds, fan speeds, and wing angle of attack. Fan thrust in crossflow was influenced by two principal factors: the effects of inflow distortion on blade-row performance, and changes in fan stage operating point brought about by changes in back pressure ratio. In this particular fan, flow separation on the inlet bellmouth did not appear to be a serious problem for crossflow operation.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 10; Mar. 197
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  • 197
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    Publication Date: 2011-08-16
    Description: Review of oblique water and fluorocarbon injection test results obtained in experimental studies of the effects of multiple-orifice liquid injection into hypersonic air streams. The results include the finding that maximum lateral penetration from such injections increases linearly with the square root of the jet-to-freestream dynamic-pressure ratio and is proportional to an equivalent orifice diameter.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Dec. 197
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  • 198
    Publication Date: 2011-08-16
    Description: A fluid-dynamic investigation was carried out to determine the cause of intense heating observed on the lee meridian of hypersonic delta wings and also to derive means for its suppression. Several experimental techniques were combined with analysis of extensive heat-transfer measurements at a freestream Mach number of six in a range of Reynolds number to acquire a general description of the lee-flow structure. With attached leading-edge flow on the delta wings, the dominant feature is a pair of embedded vortices on the lee meridian whose interaction with the boundary-layer is responsible for the observed local heating. On the basis of flow visualization results and heat-transfer correlations, a qualitative vortex flow model is proposed which differs essentially from the conventional inboard separation vortex model.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Nov. 197
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  • 199
    Publication Date: 2011-08-16
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 9; Oct. 197
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  • 200
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    Publication Date: 2011-08-16
    Description: Results are presented of some numerical experiments on simple planar configurations. The experiments serve to establish more precisely some ground rules for optimum lattice arrangements. In particular, the location of both the horseshoe vortex elements and the control points at which the surface boundary conditions are to be satisfied is uniquely determined. Questions of lattice arrangement are discussed together with numerical results and problems of control point location.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 10; May 1973
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