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  • Other Sources  (822)
  • AERODYNAMICS  (383)
  • FLUID MECHANICS AND HEAT TRANSFER  (220)
  • INSTRUMENTATION AND PHOTOGRAPHY  (219)
  • Analytical Chemistry and Spectroscopy
  • Animals
  • Life and Medical Sciences
  • Physics
  • 1975-1979  (822)
  • 1925-1929
  • 1977  (822)
Collection
Source
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  • 1975-1979  (822)
  • 1925-1929
Year
  • 1
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    Transonic/supersonic inlet R and D past, present, and future (1977)
    In:  CASI
    Details
    Publication Date: 2004-10-07
    Keywords: AERODYNAMICS
    Type: NASA Lewis Research Center Inlet Workshop; p 427-480
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  • 2
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    Comments on wind-tunnel-flight correlations for the F-8 supercritical wing configurations (1977)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 111-120
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  • 3
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    Flow phenomena peculiar to calculation of compressible turbulent boundary layers (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Calculation procedures for compressible turbulent boundary layers were based upon techniques, modeling constants, etc., developed originally for the low speed case. Significant differences and new or altered physics which occur in the compressible case were considered, as compared with the low speed situation. Possible pitfalls and sources of inaccuracy in the calculations were indicated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 9-46
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  • 4
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    Instrumentation for space flight experiments (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The selection of measurement systems for experiments conducted in the context of a space flight must be guided by the criteria applicable to any scientific study requiring objective measurements of physiological variables. Steps fundamental to the process of choosing the best instrumentation system are identified and the key factors in matching the operational characteristics of the instrumentation to its intended use are discussed. Special problems in obtaining data from nonhuman primates, whether restrained or unrestrained, are explored. Choices for data processing are evaluated as well as the use of prototype flight tests and simulations to assess future life science experiments for spacelab or payloads for the space shuttle biomedical scientific satellite.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Use of Nonhuman Primates in Space; p 225-243
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  • 5
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    Aircraft (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The physical principles of flight, and the consideration of atmospheric composition and aerodynamic forces in the design and construction of various types of aircraft are discussed. Flight characteristics are described for helicopters, rotary-wing aircraft, short and vertical takeoff aircraft, and tailess or variable geometry wing aircraft. Flow characteristics at various speeds are also discussed.
    Keywords: AERODYNAMICS
    Type: Soviet Aircraft and Rockets (NASA-TT-F-770); p 24-80
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  • 6
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    Summary of calculation procedures for nonsimilar two- and three-dimensional compressible turbulent boundary layers (finite difference, finite element and weighted residual methods), appendix (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: This numerical prediction summary indicates the wide variety of such procedures which are available. Most procedures have detailed user manuals, and in many cases the codes are available. Many of the special effects treated by various methods (such as nonequilibrium or equilibrium chemistry, transition, roughness etc.) are indicated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 69-78
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  • 7
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    Calculation of three-dimensional compressible turbulent boundary layers (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: From comparisons of high speed data with low speed closure procedures using variable mean density, there does not appear to be any appreciable influence of compressibility upon turbulent shear stress modeling in compressible turbulent boundary layers, even for extreme cases such as Mach 14 to 20 with a change in density across the layer of up to a factor of 100. Other evidence of apparent lack of compressibility caused new physics which may alter the shear stress for the compressible boundary layer cases including: (1) fluctuation Mach number was generally less than 1; (2) the shear stress distribution through the boundary layer was not a function of Mach number for zero pressure gradient flows; (3) the Morkovin hypothesis was valid up to Mach 5 (based on fluctuation data); (4) profile N power was not a function of Mach number, at least up to Mach 10; and (5) the nondimensional burst period was approximately the same as that for low speed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 47-68
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  • 8
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    Equations and closure methods (1977)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Basic differential equations governing compressible turbulent boundary layer flow are reviewed, including conservation of mass and energy, momentum equations derived from Navier-Stokes equations, and equations of state. Closure procedures were broken down into: (1) simple or zeroth-order methods, (2) first-order or mean field closure methods, and (3) second-order or mean turbulence field methods.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Calculation Methods for Compressible Turbulent Boundary Layers, 1976; p 6-8
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  • 9
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    Mass-dependent channel electron multiplier operation (1977)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The absolute counting efficiency and pulse height distributions of a continuous-channel electron multiplier used in the detection of hydrogen, argon and xenon ions are assessed. The assessment technique, which involves the post-acceleration of 8-eV ion beams to energies from 100 to 4000 eV, provides information on counting efficiency versus post-acceleration voltage characteristics over a wide range of ion mass. The charge pulse height distributions for H2 (+), A (+) and Xe (+) were measured by operating the experimental apparatus in a marginally gain-saturated mode. It was found that gain saturation occurs at lower channel multiplier operating voltages for light ions such as H2 (+) than for the heavier ions A (+) and Xe (+), suggesting that the technique may be used to discriminate between these two classes of ions in electrostatic analyzers.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 48; Aug. 197
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  • 10
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    Galatry profile convolved with the Fabry-Perot instrument function (1977)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The physical conditions in laboratory gases and in the upper atmosphere of the planets, including earth, can be deduced from a measurement of the intensity and line profile of different radiating molecules. Because of the low pressures in the upper atmospheres, many molecular lines with small pressure-broadening coefficients are collisionally narrowed. These lines are resolvable with a Fabry-Perot interferometer. Analytical expressions are given relating the measured line intensity and profile to the true line intensity and profile. A deconvolution of the measured profile gives the parameters A, beta, and K characterizing the collisionally narrowed Galatry profile. General expressions for the nonideal interferometer are discussed, and, specifically, mirror defects and a limited detector aperture are treated.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; June 197
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  • 11
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    Three-dimensional low Reynolds number flows with a free surface (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The two-dimensional leveling problem (Degani, Gutfinger, 1976) is extended to three dimensions in the case where the flow Re number is very low and attention is paid to the free surface boundary condition with surface tension effects included. The no-slip boundary condition on the wall is observed. The numerical solution falls back on the Marker and Cell (MAC) method (Harlow and Welch, 1965) with the computation region divided into a finite number of stationary rectangular cells (or boxes in the 3-D case) and fluid flow traverses the cells (or boxes).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics; 24; May 1977
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  • 12
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    A CW ultrasonic bolt-strain monitor (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: There exists a need for a relatively inexpensive system for measuring strain in bolts. The torque wrench is one technique for straining bolts which has been widely applied. Unfortunately, friction in the bolt threads and between the nut and the work tend to make such a simple system inaccurate. In practice, a torque wrench is unacceptable for many situations where strain is critical. In this article, an ultrasonic technique is described which can indicate changes in bolt strain to better than one part in 10,000. The technique is based on the one-dimensional propagating-ultrasonic-wave model and uses a new ultrasonic instrument called a Reflection Oscillator Ultrasonic Spectrometer which is a closed-loop feedback marginal-oscillator system that frequency locks the device to the peak of a mechanical resonance in the bolt. The instrument indicates a shift in the bolt resonance frequency due to elongation and changes in velocity of sound due to strain. Data are presented comparing a standard torque wrench to the ultrasonic monitor for different measured stresses on the bolt as well as for different bolt conditions. The strain instrument can be used to monitor changing stresses, to measure material properties and may be applied as a strain gage or load cell.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Experimental Mechanics; 17; May 1977
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  • 13
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    Numerical solution for subcritical flows by a transonic integral equation method (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The method presented makes use of a division of the region of integration into closed rectangular elements. The velocity is taken to be constant in each element. The integral equation is reduced to a matrix equation which can be solved by an appropriate iteration approach. The derivation and solution of the matrix equation are discussed and the matrix elements are considered. The described concepts were implemented for a nonlifting parabolic-arc airfoil.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; Mar. 197
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  • 14
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    Derivation of an integral equation for transonic flows (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: It is noted that the nonlinear partial differential equation for the perturbation velocity potential and boundary conditions describing steady inviscid compressible transonic flow past a thin two-dimensional airfoil can be transformed into a singular integrodifferential equation and that differentiation of the latter yields an integral equation. Two forms of this integral equation currently exist: one for the singularity that is enclosed in an infinitely long strip of vanishing thickness and the other for the singularity that is enclosed in a vanishing circle. In the present article, a more general integral equation is derived by enclosing the singularity in a vanishing rectangular cavity of arbitrary aspect ratio. The two existing forms of this equation are deduced as special cases distinguished by the respective values for the aspect ratio (infinity for the first form and unity for the second).
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; Feb. 197
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  • 15
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    Flow characteristics in an expansion tunnel as inferred from velocity measurements (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A photoionization technique was used to study flow characteristics in an expansion tunnel. Vertical surveys of the axial component of flow velocity just downstream from the nozzle exit were obtained, and estimates of freestream density were inferred from the velocity measurement technique. The pitot pressure was measured and compared to the average axial component of velocity as a function of time for the two cases when air and CO2 were used as test gases. Vertical velocity and static density profiles at the nozzle exit are presented for the case when CO2 was used as test gas. Experimental results were used to determine the diameter and uniformity of the test core at the nozzle exit and the duration of the quasi-steady flow period. These data are relevant to evaluation of the suitability of operating an expansion tube as an expansion tunnel. The expansion tunnel is an expansion tube with a conical nozzle positioned at the exit of the acceleration section, so that nozzle entrance flow conditions are hypersonic and characterized by hypervelocity.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; Sept
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  • 16
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    Quasi-microscope concept for planetary missions (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Viking lander cameras have returned stereo and multispectral views of the Martian surface with a resolution that approaches 2 mm/lp in the near field. A two-orders-of-magnitude increase in resolution could be obtained for collected surface samples by augmenting these cameras with auxiliary optics that would neither impose special camera design requirements nor limit the cameras field of view of the terrain. Quasi-microscope images would provide valuable data on the physical and chemical characteristics of planetary regoliths.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Sept
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  • 17
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    Kinetic theory analysis of rarefied gas flow through finite length slots (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A kinetic-theory analysis is made of the flow of a rarefied monatomic gas through a two-dimensional slot connecting two reservoirs. Numerical solutions are obtained by the moment and discrete-ordinate methods. The former method portrays the transition-regime characteristics well but has limitations in the free-molecule regime. The latter method gives accurate results in the free-molecule and slip regimes and bolsters confidence in the accuracy of the transition-regime results. The numerical solution for the mass flux through the slot agrees well with an approximate analytical solution of the moment equations for length-to-width ratios from 6 to 0.5, pressure ratios from 0.8 to 0.1, and Knudsen numbers from 5 to 0.5.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 20; June 197
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  • 18
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    Low Reynolds number flow past a blunt axisymmetric body at angle of attack (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Low Reynolds number flow of an ideal gas over a blunt axisymmetric body of large half-angle at small angles of attack is investigated, for the case of laminar hypersonic flow. Time-varying viscous shock layer equations describing the flowfield are obtained from the full Navier-Stokes system by keeping terms to second order in the inverse square root of Re in both viscous and inviscid regions; the equations are valid for moderate to high Re. Drag, skin friction, and heating rates were obtained at small (or zero) angles of attack. Conditions experienced by planetary entry probes during the high-altitude (early) legs of an atmospheric entry trajectory are pertinent to the problem.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; Aug. 197
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  • 19
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    Evaluation of flight spoilers for vortex alleviation (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper describes the facilities and test procedures used in a series of wind-tunnel and full-scale flight investigations of the effectiveness of flight spoilers currently existing on wide-bodied transport jet aircraft when used as trailing vortex hazard alleviation devices. Examples of the results of such studies include the variation of trailing wing rolling-moment coefficient with downstream distance behind a B-747 airplane model with various segments of its flight spoilers deflected 45 deg, and comparisons with models without spoilers deflected. It is concluded that the existing flight spoilers on the B-747 are effective as trailing vortex attenuators.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 14; Aug. 197
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  • 20
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    The effect of ablation injection on radiative and convective heating (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A viscous shock-layer analysis for calculating high energy equilibrium flow fields about blunt axisymmetric bodies is applied to the problem of massive ablation injection with radiation transport. A nongray radiation model is used that accounts for both line and continuum radiation. The solution method is direct and provides both stagnation and downstream solutions. Results for shock heated air show that phenolic-nylon injection is substantially more effective in reducing the wall radiant flux than air injection. Also, for large included body angles, the wall radiative flux and the coupled phenolic-nylon injection rate do not continue to decrease with increasing distance downstream.
    Keywords: AERODYNAMICS
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  • 21
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    Comment on 'Drag coefficient of spheres in continuum and rarefied flows' (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A paper by Henderson (1976) provides a method of predicting experimental sphere drag data. This approach uses two equations for the drag coefficient, one for relative Mach number less than one, one for relative Mach number greater than 1.75. For relative Mach numbers between these limits a linear interpolation procedure is followed. In a comment on this paper, it is claimed, on the basis of comparing predictions with experimental results, that a method proposed by Walsh (1975) gives better predictions of the drag coefficient for relative Mach numbers less than 1.75, provided that a modification of the procedure is made for relative Mach numbers less than 0.1. For values over 1.75, both methods are considered equally accurate. In a reply to this comment, it is agreed that the Walsh method is more accurate when Reynolds numbers are within a range between 20 and 200, and Mach numbers are between 0.5 and 1.25. Presumed errors and possible limitations in the Walsh procedure for predicting drag coefficients are discussed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; June 197
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  • 22
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    Maximum theoretical angular accuracy of planar and linear arrays of sensors (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The maximum theoretical accuracy in the angular location of a radiating object that can be obtained by using a planar or linear array is studied. The elements are assumed to have identical radiation patterns and the complex voltages observed at their ports are assumed to be subject to phase measurement errors, having normal probability density. An optimum scheme for the statistical extraction of the parameters defining the direction is established noting that the presence of thermal noise does not affect the structure of the estimator. Comparisons with the conventional multiple interferometric techniques are made.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Aerospace and Electronic Systems; AES-13; Mar. 197
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  • 23
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    Ultraviolet response of InGaAsP photocathodes (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Three type VPM 164 photomultiplier tubes with III-IV compound InGaAsP reflective photocathodes were developed for use in ground-based and space-borne astronomical detectors. Although the achieved response of about 0.02% quantum efficiency at 1.083 microns fell short of the goal of 1% quantum efficiency, the broadband characteristics are still considerably better than those of the S-1 photocathode.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Apr. 197
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  • 24
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    Airborne bathymetric charting using pulsed blue-green lasers (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Laboratory and airborne experiments have proven the feasibility and demonstrated the techniques of an airborne pulsed laser system for rapidly mapping coastal water bathymetry. Water depths of 10 plus or minus 0.25 m were recorded in waters having an effective attenuation coefficient of 0.175 m. A 2-MW peak power Nd:YAG pulsed laser was flown at an altitude of 600 m. An advanced system, incorporating a mirror scanner, a high pulsed rate laser, and a good signal processor, could survey coastal zones at the rate of several square miles per hour.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Jan. 197
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  • 25
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    Problems in the use of interference filters for spectrophotometric determination of total ozone (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An analysis of the use of ultraviolet narrow-band interference filters for total ozone determination is given with reference to the New Zealand filter spectrophotometer under the headings of filter monochromaticity, temperature dependence, orientation dependence, aging, and specification tolerances and nonuniformity. Quantitative details of each problem are given, together with the means used to overcome them in the New Zealand instrument. The tuning of the instrument's filter center wavelengths to a common set of values by tilting the filters is also described, along with a simple calibration method used to adjust and set these center wavelengths.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Meteorology; 16; Aug. 197
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  • 26
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    Vortex lattice prediction of subsonic aerodynamics of hypersonic vehicle concepts (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The vortex lattice method introduced by Lamar and Gloss (1975) was applied to the prediction of subsonic aerodynamic characteristics of hypersonic body-wing configurations. The reliability of the method was assessed through comparison of the calculated and observed aerodynamic performances of two National Hypersonic Flight Research Facility craft at Mach 0.2. The investigation indicated that a vortex lattice model involving 120 or more panel elements can give good results for the lift and induced drag coefficients of the craft, as well as for the pitching moment at angles of attack below 10 to 15 deg. Automated processes for calculating the local slopes of mean-camber surfaces may also render the method suitable for use in preliminary design phases.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 14; Oct. 197
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  • 27
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    Liquid helium-cooled MOSFET preamplifier for use with astronomical bolometer (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A liquid helium-cooled p-channel enhancement mode MOSFET, the 3N167, is found to have sufficiently low noise for use as a preamplifier with helium-cooled bolometers that are used in infrared astronomy. Its characteristics at 300, 77, and 4.2 K are presented. It is also shown to have useful application with certain photoconductive and photovoltaic infrared detectors.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 48; Apr. 197
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  • 28
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    Apparatus for measuring the force of gravity on freely falling electrons (1977)
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    Publication Date: 2011-08-17
    Description: An apparatus and data analysis technique for measuring the gravitational force on freely falling electrons are described. The measurement required that all forces acting on the electrons be uniform and measurable to about ten to the negative 11th power eV/m. The electrical force along the axis of the 5-cm-diam, vertical copper tube used in the experiment was found to be about six times ten to the negative 11th power eV/m when the tube was cooled to 4.2 K. Forces on electrons due to magnetic field gradients were reduced well below the electrical ones by selecting only ground state electrons for measurement. The absence, at 4.2 K, of much stronger electric fields, which were expected to arise from the patch effect and from differential lattice components, contrasts strongly with measurements of electric fields near metal surfaces made at room temperature.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 48; Jan. 197
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  • 29
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    The effect of bandwidth on filter instrument total ozone accuracy (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The effect of the width and shape of the New Zealand filter instrument's passbands on measured total-ozone accuracy is determined using a numerical model of the spectral measurement process. The model enables the calculation of corrections for the 'bandwidth-effect' error and shows that highly attenuating passband skirts and well-suppressed leakage bands are at least as important as narrow half-bandwidths. Over typical ranges of airmass and total ozone, the range in the bandwidth-effect correction is about 2% in total ozone for the filter instrument, compared with about 1% for the Dobson instrument.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Meteorology; 16; Aug. 197
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  • 30
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    Cooling effectiveness of slot injection into a turbulent boundary layer (1977)
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    Publication Date: 2011-08-17
    Description: The cooling effectiveness of injection through multiple flush slots at an angle of 10 deg was studied experimentally in a wind tunnel. Air was injected from one to four slots into a turbulent Mach 6 boundary layer. The slot mass flow ratio is defined, and data which describe the dependence of the cooling effectiveness on the slot mass flow ratio are presented. Experimental values are indicated graphically for various cases of single and multiple slot injection, where the total mass injection (i.e., the sum of flow rates from each slot) is the same for each case. The results show that, for a given coolant mass flow rate, thermal protection over the maximum surface area can be accomplished best by injecting the coolant flow through multiple slots.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; Sept
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  • 31
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    Spectral radiance calibrations between 165-300 nm - An interlaboratory comparison (1977)
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    Publication Date: 2011-08-17
    Description: The spectral radiance of deuterium lamps calibrated by the Max-Planck-Institut fuer Astronomie (MPI), by the U.S. National Bureau of Standards (NBS), and by the Physikalisch-Technische Bundesanstalt (PTB) are compared to check the agreement of UV radiometric scales. The NBS group used the optically thin continuum radiation from a wall-stabilized hydrogen arc as its fundamental radiometric standard, while the MPI and PTB groups used the synchrotron radiation facility in DESY. It is found that the spectral radiance scales based upon the DESY synchrotron and the NBS hydrogen arc are consistent, at least for one wavelength relative to another.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; July 197
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  • 32
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    A K-band radiometer for the microwave weather project (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The design of a K-band radiometer for use in the microwave weather project is discussed. The major components of the system, such as feedhorn, waveguide switch, and receiver assembly are described. The system will be installed at DSS 13 at Goldstone, California, when completed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Deep Space Network; p 66-69
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    Digital high density (80 Mb/s) tape (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Work with a state-of-the-art high density PCM tape recorder reproducer system is described. The tape recorder is designed for 80 Mb/s operation at an overall bit error rate of .00001and for 40 Mb/s operation at .000001. The article describes the process of measuring the error rate. Also detailed is a data rate buffer designed for use in recent radar experiments and generalizable to most potential uses of the recorder system.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Deep Space Network; p 110-118
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    Noise calibration repeatability of an airborne third-generation radiometer (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A third-generation S-band radiometer has been calibrated at intervals over 3.5 years. The built-in stabilization concepts have proven to be very effective. In spite of some nonideal conditions (on runway, in wind, and in rain), an rms value of 0.7-K calibration repeatability has been observed with an average temperature deviation (bias error) of 0.03 K.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Microwave Theory and Techniques; MTT-25; Oct. 197
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    Effect of compliant wall motion on turbulent boundary layers (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A critical analysis of available compliant wall data which indicated drag reduction under turbulent boundary layers is presented. Detailed structural dynamic calculations suggest that the surfaces responded in a resonant, rather than a compliant, manner. Alternate explanations are given for drag reductions observed in two classes of experiments: (1) flexible pipe flows and (2) water-backed membranes in air. Analysis indicates that the wall motion for the remaining data is typified by short wavelengths in agreement with the requirements of a possible compliant wall drag reduction mechanism recently suggested by Langley.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    An implicit-iterative solution of the heat conduction equation with a radiation boundary condition (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: For the problem of predicting one-dimensional heat transfer between conducting and radiating mediums by an implicit finite difference method, four different formulations were used to approximate the surface radiation boundary condition while retaining an implicit formulation for the interior temperature nodes. These formulations are an explicit boundary condition, a linearized boundary condition, an iterative boundary condition, and a semi-iterative boundary method. The results of these methods in predicting surface temperature on the space shuttle orbiter thermal protection system model under a variety of heating rates were compared. The iterative technique caused the surface temperature to be bounded at each step. While the linearized and explicit methods were generally more efficient, the iterative and semi-iterative techniques provided a realistic surface temperature response without requiring step size control techniques.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal for Numerical Methods in Engineering; 11; 10, 1; 1977
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    Wall cooling effects on hypersonic transitional/turbulent boundary layers at high Reynolds numbers (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The characteristics of a thick hypersonic boundary layer turbulent for a length of 175 cm on a 4 deg sharp wedge were measured. The resulting boundary layer was free from transverse curvature effects and only mildly affected by upstream history effects caused by pressure and wall temperature gradients. Heat-transfer distributions were used to locate regions of laminar, transitional, and turbulent flow at an edge unit Reynolds number of 470,000 cm at wall-to-total temperature ratios from about 0.3 to 1. Wall cooling had little effect on the location of the transition region. Pitot and total temperature profiles and skin-friction measurements were obtained at several locations along the model longitudinal centerline. Mixing length and turbulent Prandtl number distributions were derived from the fully turbulent mean profiles.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; Oct. 197
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    Instrumental sensing of stationary source emissions (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A variety of programs have been conducted within EPA to evaluate the capability of various ground-based remote-sensing techniques for measuring the SO2 concentration, velocity, and opacity of effluents from coal-burning power plants. The results of the remote measurements were compared with the results of instack measurements made using EPA reference methods. Attention is given to infrared gas-filter correlation radiometry for SO2 concentration, Fourier-transform infrared spectroscopy for SO2 concentration, ultraviolet matched-filter correlation spectroscopy for SO2 concentration, infrared and ultraviolet television for velocity and SO2 concentration, infrared laser-Doppler velocimetry for plume velocity, and visible laser radar for plume opacity.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Environmental Science and Technology; 11; Oct. 197
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    VLBI clock sync and the earth's rotational instability (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Preparation is being made by the DSN to monitor the stability of its clocks and frequency standards in the 64 meter net by means of VLBI. Since variations in the earth's rotation rate represent an error source to VLBI clock synchronization, the Allan Variance of the earth rotation was calculated to find that, in a long-term sense at least, these variations do not noticeably increase the differential instability of two clocks as measured by Intercontinental VLBI.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Deep Space Network; p 81-84
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    Numerical turbulence modeling (1977)
    In:  CASI
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    Publication Date: 2012-05-19
    Description: The underlying bases and developments in two techniques of detailed turbulence modeling are described where the flow is treated in the Eulerian sense, and one technique where the Lagrangian motions of vortices are followed. First, a technique is described for solving the single-point statistically averaged conservation equations. The Reynolds stresses that appear in these equations are evaluated by solving supplemental differential equations which contain terms that are modeled. A sequence of increasingly complex, but also increasingly general, modeling equations is described and computations based on these equations are compared with experimental data. The hierarchy of models described terminates with equations for the individual components of the Reynolds stress tensor. The second Eulerian technique approach to turbulence modeling is the direct numerical simulation of turbulent fields. In this approach, all three dimensional eddies between a predetermined range of sizes are computed in time within a specified volume of flow. Present day computers require a tradeoff between the size of the volume that can be considered and the degree of resolution of the turbulent eddies. Techniques of modeling the smallest eddies are described that permit enlarging the volume, or Reynolds number, that can be considered.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD Computational Fluid Dyn.; 37 p
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    Variable temperature pressure cell for polycrystalline X-ray studies down to 2 K - Application to Bi (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A variable pressure diamond anvil cell is described for operation at temperatures continuously variable from 300 down to 2 K and controllable within 10 mK. Polycrystalline X-ray data are collected from the pressure cavity by means of either (1) standard photographic techniques, (2) diffractometer measurements, or (3) energy dispersive diffractometry. The facility has been used to examine parts of the phase diagram of Bi. Results from this study indicate that the Bi-I and Bi-III structures are retained to low temperatures; however, there is no evidence to support a structural transition from Bi-V to Bi-VIII.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 48; July 197
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    Primary aberrations for grazing incidence (1977)
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    Publication Date: 2011-08-17
    Description: Beginning with exact relations between object and image coordinates for a single reflective surface, a systematic analysis of general grazing incidence systems is presented. A complete set of primary aberrations for single-element and two-element systems is developed. The importance of a judicious choice for a coordinate system in showing field curvature to be clearly the predominant aberration for a two-element system is discussed. The validity of the theory is verified through comparisons with the exact ray-trace results for the case of a telescope.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Sept
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    Application of the high resolution return beam vidicon (1977)
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    Publication Date: 2011-08-17
    Description: The Return Beam Vidicon (RBV) is a high-performance electronic image sensor and electrical storage component. It can accept continuous or discrete exposures. Information can be read out with a single scan or with many repetitive scans for either signal processing or display. Resolution capability is 10,000 TV lines/height, and at 100 lp/mm, performance matches or exceeds that of film, particularly with low-contrast imagery. Electronic zoom can be employed effectively for image magnification and data compression. The high performance and flexibility of the RBV permit wide application in systems for reconnaissance, scan conversion, information storage and retrieval, and automatic inspection and test. This paper summarizes the characteristics and performance parameters of the RBV and cites examples of feasible applications.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Engineering; 16; May-June
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    Prediction of outer layer mixing lengths in turbulent boundary layers (1977)
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    Publication Date: 2011-08-17
    Description: Predictions of mixing length by Pletcher's (1976) method (using a two-layer eddy viscosity model for a turbulent boundary layer at low Reynolds numbers) are compared to some values derived from turbulent boundary-layer profiles by other authors. The model is incorporated into a finite-difference scheme, to accurately predict low Reynolds number skin friction in supersonic flow.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 15; Apr. 197
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    Photographic film and the Skylab environment (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An overview is presented of an investigation which was conducted to determine the actual effects of the Skylab environment on flight films. Examples of the flight film performance data are provided. Attention is given to the Skylab film, the environmental parameters, a major events profile of the Skylab mission, and a film environmental effects analysis. Representative Skylab film environmental response data are shown in a graph.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Apr. 197
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    Application of the method of integral relations to laminar boundary layers in three dimensions (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The method of integral relations is extended to general three-dimensional compressible laminar boundary layer flows. The transformation employed to transform the basic three-dimensional compressible boundary layer equations into quasi-incompressible form is an extension of the Howarth transformation. The resulting system of differential equations is integrated numerically by the method of integral relations as proposed by Dorodnitsyn. To demonstrate the accuracy of the method, it is applied to calculation of the parabolic flow over a flat plate and the boundary flow over an infinite yawed cylinder, for which solutions are known. It is then applied to the flow over a flat plate disturbed by a cylinder normal to the plate, for which a finite-difference solution is available for comparison. It is finally applied to calculating the crossflow velocity variation for supersonic flow over a swept wedge.
    Keywords: AERODYNAMICS
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    A novel concept for subsonic inlet boundary-layer control (1977)
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    Publication Date: 2011-08-17
    Description: A self-bleeding method for boundary layer control is described and tested for a subsonic inlet designed to operate in the flowfield generated by high angles of attack. Naturally occurring surface static pressure gradients are used to remove the boundary layer from a separation-prone region of the inlet and to reinject it at a less critical location with a net performance gain. The results suggest that this self-bleeding method for boundary-layer control might be successfully applied to other inlets operating at extreme aerodynamic conditions.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 14; Apr. 197
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    Experimental study of error sources in skin-friction balance measurements (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An experimental study has been performed to determine potential error sources in skin-friction balance measurements. A floating-element balance, large enough to contain the instrumentation needed to systematically investigate these error sources has been constructed and tested in the thick turbulent boundary layer on the sidewall of a large supersonic wind tunnel. Test variables include element-to-case misalignment, gap size, and Reynolds number. The effects of these variables on the friction, lip, and normal forces have been analyzed. It was found that larger gap sizes were preferable to smaller ones; that small element recession below the surrounding test surface produced errors comparable to the same amount of protrusion above the test surface; and that normal forces on the element were, in some cases, large compared to the friction force.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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    Mach 6 flowfield survey at the engine inlet of a research airplane (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A flowfield survey was conducted to better define the nature of vehicle forebody flowfield at the inlet location of an airframe-integrated scramjet engine mounted on the lower surface of a high-speed research airplane to be air launched from a B-52 and rocket boosted to Mach 6. The tests were conducted on a 1/30-scale brass model in a Mach-6 20-in. wind tunnel at Reynolds number of 11,200,000 based on distance to engine inlet. Boundary layer profiles at five spanwise locations indicate that the boundary layer in the area of the forebody centerline is more than twice as thick as the boundary layer at three outboard stations. It is shown that the cold streak found in heating contours on the centerline of the forebody is caused by a thickening of the boundary layer on the centerline, and that this thickening decreases with angle of attack.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 14; Apr. 197
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    Hot-wire anemometry in transonic flow (1977)
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    Publication Date: 2011-08-17
    Description: The use of hot-wire anemometry for obtaining fluctuating data in transonic flows has been evaluated. From hot-wire heat loss correlations based on previous transonic data, the sensitivity coefficients for velocity, density, and total temperature fluctuations have been calculated for a wide range of test conditions and sensor parameters. For sensor Reynolds number greater than 20 and high sensor overheat ratios, the velocity sensitivity remains independent of Mach number and equal to the density sensitivity. These conditions were verified by comparisons of predicted sensitivities with those from recent direct calibrations in transonic flows. Based on these results, techniques are presented to obtain meaningful measurements of fluctuating velocity, density, and Reynolds shear stress using hot-wire and hot-film anemometers. Example of these measurements are presented for two transonic boundary layers.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 15; Mar. 197
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    Vacuum ultraviolet radiometry. III - The argon mini-arc as a new secondary standard of spectral radiance (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A miniature argon arc has been designed and tested as a new transfer standard of spectral radiance for the wavelength range from 114 nm to 330 nm. Calibration has been performed using two primary standard sources: the hydrogen arc from 130 nm to 330 nm and the blackbody line radiator from 114 nm to 130 nm. The mini-arc provides an intense, stable, and reproducible UV continuum with dc power requirements of less than 1.5 kW. The arc characteristics have been investigated, and the sensitivity of the radiant power output to various operating parameters has been measured. The rms uncertainty in the spectral radiance is estimated to be 5.3% above 140 nm and 10.1% between 114 nm and 140 nm, due primarily to uncertainties in the primary standard sources.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Feb. 197
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    Slow scan SEC vidicon system (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A slow scan SEC vidicon system is described here. This system is coupled to the 152.4-cm (60-in) McMath telescope at Kitt Peak National Observatory. An anamorphic lens system is used to couple optically the vertical spectrograph to the vidicon system. The resolutin of the over-all system is 55 mA, while the resolution of the spectrograph alone is 50 mA. Actual observational results are used to evaluate the system performance.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Jan. 197
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    A block iterative finite element algorithm for numerical solution of the steady-state, compressible Navier-Stokes equations (1977)
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    Publication Date: 2011-08-17
    Description: An iterative method for numerically solving the time independent Navier-Stokes equations for viscous compressible flows is presented. The method is based upon partial application of the Gauss-Seidel principle in block form to the systems of the nonlinear algebraic equations which arise in construction of finite element (Galerkin) models approximating solutions of fluid dynamic problems. The continuous cubic element on triangles is employed for function approximation. Computational results for a free shear flow at Re = 1000 indicate significant achievement of economy in iterative convergence rate over finite element and finite difference models which employ the customary time dependent equations and symptotic time marching procedure to steady solution. Numerical results are in excellent agreement with those obtained for the same test problem employing time marching finite element and finite difference solution techniques.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal for Numerical Methods in Engineering; 11; 12, 1; 1977
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    Single-axis gyroscopic motion with uncertain angular velocity about spin axis (1977)
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    Publication Date: 2011-08-17
    Description: A differential game approach is presented for studying the response of a gyro by treating the controlled angular velocity about the input axis as the evader, and the bounded but uncertain angular velocity about the spin axis as the pursuer. When the uncertain angular velocity about the spin axis desires to force the gyro to saturation a differential game problem with two terminal surfaces results, whereas when the evader desires to attain the equilibrium state the usual game with single terminal manifold arises. A barrier, delineating the capture zone (CZ) in which the gyro can attain saturation and the escape zone (EZ) in which the evader avoids saturation is obtained. The CZ is further delineated into two subregions such that the states in each subregion can be forced on a definite target manifold. The application of the game theoretic approach to Control Moment Gyro is briefly discussed.
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    Condensation heat transfer in rotating heat pipes in the presence of a non-condensable gas (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An analysis of condensation problems in rotating heat pipes containing vapors with different concentrations of non-condensable gases is given. In situations such as this, temperature and concentration gradients are set up in the vapor-gas mixture. There is a transport of mass due to temperature gradients accompanied by an energy transport phenomena due to a concentration gradient. A Nusselt type analysis is not suited to this type of problem; however, a boundary layer type approach has successfully been used to analyze stationary condensation systems with non-condensable gases present. The present boundary layer analysis is presented for condensation processes on the inside of a rotating heat pipe in the presence of non-condensable gases.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Revue Roumaine des Sciences Techniques; vol. 22
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    Comparison of numerical and experimental 'conical' flow fields in supersonic corners with compression and/or expansion (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The flow field produced by the intersection of two plane solid surfaces in a supersonic stream is a complex interference flow. These flows can be fully compressive, fully expansive, or of mixed compression-expansion nature. This paper presents a comparison of the experimentally obtained flow-field structure in an axial corner with that predicted numerically by using a shock-capturing finite-difference method. The effect of sweep and surface deflection are evaluated, and the general influence of each is presented for the three classes of corner flow. The results show that the numerical method is a valuable aid in understanding the flow structure for simple configurations. In addition, confidence in the numerical method is gained for use in solving more general three-dimensional configurations where the flow is nonconical and several wave interaction may be presented.
    Keywords: AERODYNAMICS
    Type: British Aircraft Corp.
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    Unsteady flow in a supersonic cascade with strong in-passage shocks (1977)
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    Publication Date: 2011-08-17
    Description: Linearized theory is used to study the unsteady flow in a supersonic cascade with in-passage shock waves. We use the Wiener-Hopf technique to obtain a closed-form analytical solution for the supersonic region. To obtain a solution for the rotational flow in the subsonic region we must solve an infinite set of linear algebraic equations. The analysis shows that it is possible to correlate quantitatively the oscillatory shock motion with the Kutta condition at the trailing edges of the blades. This feature allows us to account for the effect of shock motion on the stability of the cascade. Unlike the theory for a completely supersonic flow, the present study predicts the occurrence of supersonic bending flutter. It therefore provides a possible explanation for the bending flutter that has recently been detected in aircraft-engine compressors at higher blade loadings.
    Keywords: AERODYNAMICS
    Type: Journal of Fluid Mechanics; 83; Dec. 5
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    Estimation of spectral reflectance curves from multispectral image data (1977)
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    Publication Date: 2011-08-17
    Description: A technique is presented for estimating spectral reflectance curves from multispectral image data even if the spectral samples are obtained from channels whose spectral responsivity is not narrowband. It is demonstrated that these reflectance estimates can be written as a linear combination of the spectral samples and that, analogous to Shannon's sampling theorem, if the spectral reflectance is a natural cubic spline, it can be estimated exactly provided the number of spectral channels is sufficiently large. Simulation results suggest that the accuracy of the spectral reflectance estimates is quite good and very insensitive to the spectral responsivity shapes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Dec. 197
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    Correlation of turbulent shear layer attachment peak heating near Mach 6 (1977)
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    Publication Date: 2011-08-17
    Description: A correlation of new turbulent two-dimensional data and peak heating data for attaching free shear layers is presented for a 2.54-cm and 5.08-cm diam cylindrical leading-edge slab 25.4 cm long, and 7.62 and 10.16 cm wide. A 30.48 x 25.4 cm sharp leading-edge flat plate set at 15 and 20 deg is used to generate plane impinging shocks. The freestream Mach number is 6 and the freestream Reynolds number varies from 3,300,000 to 25,600,000/m. Peak heating is measured on silica-based epoxy models with a phase change coating technique. A comparison of the free shear layer data with the transition data of Birch and Keyes (1972) reveals that the shear layer data are turbulent at attachment. The trend of the data shows that peak heating is strongly affected by the state of development at attachment. As the free shear layers become more fully developed, the data approach the two-dimensional correlation. Persistence of transitional flow structures for supersonic free shear flows is pointed out.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 15; Dec. 197
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    Calculated heating on the afterbody nozzle of a hypersonic aircraft concept (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The present analysis was carried out to estimate the heating levels of the external nozzle of a scramjet/airframe-integrated research aircraft. A parametric examination of the effects of Mach number, reference length, and wall temperature showed that the heating rate distributions are independent of reference length and wall temperature. The initial heating rates obtained for a Mach 6 flight are in the (3 to 8) x 10 to the 5th power W/sq m range. Underlying the entire study is the question of nozzle boundary layer formation and growth, as well as the question of the reference length value that should be used in the computations. It is shown that the reference length is not the dominant factor setting the heating levels; an attempt to bound the actual length was made. A more detailed calculation of the rates requires further work to gain a better understanding of the combustor exit boundary layer.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 14; Dec. 197
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    Revised international representations for the viscosity of water and steam and new representations for the surface tension of water (1977)
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    Publication Date: 2011-08-17
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Spectral interpolation - Zero fill or convolution (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Zero fill, or augmentation by zeros, is a method used in conjunction with fast Fourier transforms to obtain spectral spacing at intervals closer than obtainable from the original input data set. In the present paper, an interpolation technique (interpolation by repetitive convolution) is proposed which yields values accurate enough for plotting purposes and which lie within the limits of calibration accuracies. The technique is shown to operate faster than zero fill, since fewer operations are required. The major advantages of interpolation by repetitive convolution are that efficient use of memory is possible (thus avoiding the difficulties encountered in decimation in time FFTs) and that is is easy to implement.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 16; Nov. 197
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    Evaluation of a hydrogen chloride detector for environmental monitoring (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper describes a hydrogen chloride detector designed to monitor concentrations of hydrogen chloride gas in the ambient environment. The detector was developed for NASA for use in launch vehicle effluent monitoring. The detector operates on chemiluminescence principles with a lower detection limit of less than 5 x 10 to the -3rd ppm (by volume). The hydrogen chloride in the air sample reacts with a bromide-bromate coating in the inlet tube of the instrument producing bromine. Bromine is then quantitated by chemiluminescent oxidation of luminol. The visible light generated in the chemiluminescent reaction is proportional to the hydrogen chloride concentration of the sampled airstream. The detector is most suited to laboratory or field studies where hydrogen chloride is the dominant pollutant, as compared to the interfering species. Interferences include strong acids, acid-forming gases, and halogen gases. Of the interferences investigated the most serious in these groups are hydrochloric and sulfuric acid, sulfur dioxide, and chlorine, respectively. The detector has been in use since 1974 and has been found to be highly portable, rugged, and stable under extreme environmental conditions.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 48; Nov. 197
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  • 64
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    Monte Carlo turbulence simulation (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper describes turbulence simulation experiments based on the principles of control system theory, that is, the construction of a system characterized by a system function such that upon exciting the system with prescribed noise processes the output of the system is a realization of a random processing the desired statistical attributes of turbulence. An experimental autocorrelation of Jimsphere measurements of wind velocity was approximated to simulate turbulent wind. From the approximate autocorrelation function, the required system function is obtained, and a discrete time system is designed. Another method of simulation is to solve the convolution integral by filter techniques. Other methods include discrete Fourier simulation and self-similar simulation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 65
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    Optical and acoustical measuring techniques (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper reviews the techniques of laser and acoustic Doppler measurement of fluid velocities in confined and free flows. The main mathematical relations are presented, and some systems are studied. Resolution properties of coaxial, bistatic, and pulsed CO2 laser Doppler velocimeter systems are compared. Schematics for pulsed and continuous wave acoustic Doppler systems are discussed. Both of these types of systems benefit from using a bistatic configuration instead of a coaxial system. The pulsed systems avoid contamination of source noise by not sampling until after the source noise has passed the receiver. Comparison of wind velocity measured with a pulsed acoustic Doppler and with a boundary layer profile is made.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 66
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    Turbulence processes and simple closure schemes (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The problem of closure in turbulence in the case of two-point correlations resides in the existence of two unknowns E and W, the energy spectrum function and the transfer function, respectively, in the spectrum equation. In the case of weak turbulence, W is negligible. In case of higher correlations, closure can be effective by neglecting the inertia term in the highest order term used. Specifying a certain number of spectra at an initial time is also a way of getting around the closure problem. A simple case of turbulent shear flow is then considered, where two-point correlation equations are used and the velocity is broken into mean and fluctuating components. This yields a differential equation for the energy spectrum, the three terms of which are the energy spectrum, production term and dissipation term. They are plotted for a particular time. Similar analyses and comparisons with experiment are made for pipe and boundary layer flows.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 67
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    Auger spectroscopy analysis in adhesion, friction and wear studies (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper reviews the current use of Auger electron spectroscopy in adhesion, friction, wear and lubrication studies. Conventional Auger spectroscopy is adopted to complement LEED studies of the adhesion of metal single crystals. In addition, Auger cylindrical mirror analysis is applied to the study of changes in surface chemistry during dynamic friction and wear experiments on polycrystalline metals and alloys. Important conclusions are that (1) segregation of alloying elements to the surface of metals can alter adhesion behavior; (2) hydrocarbons are adsorbed readily to clean iron surfaces at 23 C; (3) transfer from one surface to another for dissimilar materials in contact can be followed in sliding or rubbing friction studies; and (4) the friction process can enhance surface activity for metals with hydrocarbons.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Advances in Nondestructive Testing; 5; 1977
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  • 68
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    Aerodynamic characteristics at high angles of attack (1977)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An overview is presented of the aerodynamic inputs required for analysis of flight dynamics in the high-angle-of-attack regime wherein large-disturbance, nonlinear effects predominate. An outline of the presentation is presented. The discussion includes: (1) some important fundamental phenomena which determine to a large extent the aerodynamic characteristics of airplanes at high angles of attack; (2) static and dynamic aerodynamic characteristics near the stall; (3) aerodynamics of the spin; (4) test techniques used in stall/spin studies; (5) applications of aerodynamic data to problems in flight dynamics in the stall/spin area; and (6) the outlook for future research in the area.
    Keywords: AERODYNAMICS
    Type: Von Karman Inst. for Fluid Dyn. Aerodyn. Inputs for Probl. in Aircraft Dyn., Vol. 2; 39 p
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  • 69
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    Magnetic bearing momentum wheels with magnetic gimballing capability for 3-axis active attitude control and energy storage (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A 3-axis active attitude control system with only one rotating part was developed using a momentum wheel with magnetic gimballing capability as a torque actuator for all three body axes. A brief description of magnetic bearing technology is given. It is concluded that based on this technology an integrated energy storage/attitude control system with one air of counterrotating rings could reduce the complexity and weight of conventional systems.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Res. Center The 11th Aerospace Mech. Symp.; p 45-55
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  • 70
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    Vortex attenuation flight experiments (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Flight tests evaluating the effects of altered span loading, turbulence ingestion, combinations of mass and turbulence ingestion, and combinations of altered span loading turbulance ingestion on trailed wake vortex attenuation were conducted. Span loadings were altered in flight by varying the deflections of the inboard and outboard flaps on a B-747 aircraft. Turbulence ingestion was achieved in flight by mounting splines on a C-54G aircraft. Mass and turbulence ingestion was achieved in flight by varying the thrust on the B-747 aircraft. Combinations of altered span loading and turbulence ingestion were achieved in flight by installing a spoiler on a CV-990 aircraft and by deflecting the existing spoilers on a B-747 aircraft. The characteristics of the attenuated and unattenuated vortexes were determined by probing them with smaller aircraft. Acceptable separation distances for encounters with the attenuated and unattenuated vortexes are presented.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 369-403
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  • 71
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    Ground-based facilities for evaluating vortex minimization concepts (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: To determine the feasibility of altering the formation and decay of aircraft trailing vortexes through aerodynamic means, the test capabilities of two wind tunnels and two towing basins were used. The facilities, common models, and measurement techniques that were employed in the evaluation of vortex minimization concepts are described.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 129-156
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  • 72
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    Evaluation of thermal soak times (1977)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A mathematical model for the heat transfer within the electronics package of a Chaparral missile was performed. The Grashof number for this configuration was less than 2000 which indicated that the primary mode of heat transfer was conduction. The Vodicka theory for heat conduction in laminated composite media was utilized to obtain the solution for the model.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center Ninth Conf. on Space Simulation; p 435-441
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  • 73
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    High temperature strain gage evaluation (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The structural thermal test of an advanced ramjet missile section required strain measurements as high as 922 K (1200 F). Since there is relatively little experience in the use of strain gages above the 700-755 K (800-900 F) level, a program was initiated to select and evaluate the best available gage. Candidate gages suitable for measurements up to 922 K (1200 F) were selected. This involved the determination of their operating characteristics, availability, cost, installation aspects, etc. The evaluation involved the following tests: strain as a function of load at room temperature and apparent strain as a function of temperature.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Ninth Conf. on Space Simulation; p 407-423
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  • 74
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    Application of an electron beam facility for heat transfer measurements in capillary tubes (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A unique method was developed for the determination of heat transfer coefficients for water flowing through capillary tubes using a rastered electron beam heater. Heat flux levels of 150 and 500 watts/sq cm were provided on the top surface of four square tubes. Temperature gradient along the tube length and mass flow rates versus pressure drop were measured.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center Ninth Conf. on Space Simulation; p 377-391
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  • 75
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    The role of light microscopy in aerospace analytical laboratories (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Light microscopy has greatly reduced analytical flow time and added new dimensions to laboratory capability. Aerospace analytical laboratories are often confronted with problems involving contamination, wear, or material inhomogeneity. The detection of potential problems and the solution of those that develop necessitate the most sensitive and selective applications of sophisticated analytical techniques and instrumentation. This inevitably involves light microscopy. The microscope can characterize and often identify the cause of a problem in 5-15 minutes with confirmatory tests generally less than one hour. Light microscopy has and will make a very significant contribution to the analytical capabilities of aerospace laboratories.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Ninth Conf. on Space Simulation; p 277-287
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  • 76
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    Precision temperature gradient measurements on window glass (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Surface temperature gradients were measured with miniature thermocouples installed in a 58.5 cm (23-inch) square window. Test measurements at 25 locations were made under vacuum and with the window operating in radiant heat transfer mode. The analysis of thermocouple design and installation is presented along with a lead wire routing scheme to allow for both differential and absolute temperature measurements while using a minimum number of signal feedthru paths through the test chamber wall. Typical test data and operational precautions are presented along with the accuracy analysis for installation effects and measurement effects to support differential temperature measurement precision values of + or - 0.06 C RMS + or - 0.1 F RMS).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Goddard Space Flight Center Ninth Conf. on Space Simulation; p 5-14
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  • 77
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    Gravity flow rate of solids through orifices and pipes (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Lock-hopper systems are the most common means for feeding solids to and from coal conversion reactor vessels. The rate at which crushed solids flow by gravity through the vertical pipes and valves in lock-hopper systems affects the size of pipes and valves needed to meet the solids-handling requirements of the coal conversion process. Methods used to predict flow rates are described and compared with experimental data. Preliminary indications are that solids-handling systems for coal conversion processes are over-designed by a factor of 2 or 3.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the Conf. on Coal Feeding Systems; p 519-536
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  • 78
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    Ground development and flight correlation of the vortex attenuating spline device (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Data presented indicate that the wing-mounted spline is a effective vortex-attenuating device. A comparison of the vortex induced rolling moment results at a separation scale distance of 0.70 km with those measured in full scale flight indicate good agreement for the unattenuated vortex configuration. The comparison also indicates that the spline effectiveness in flight was greater than in the ground facility test. The results of an applications study show that, for the heavy commercial jet aircraft studied, use of the splines does result in some degradation of the climb gradient and rate of climb, but the aircraft should meet certification requirements.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 271-303
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  • 79
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    Application of laser velocimetry to aircraft wake-vortex measurements (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The theory and use of a laser velocimeter that makes simultaneous measurements of vertical and longitudinal velocities while rapidly scanning a flow field laterally are described, and its direct application to trailing wake-vortex research is discussed. Pertinent measurements of aircraft wake-vortex velocity distributions obtained in a wind tunnel and water towing tank are presented. The utility of the velocimeter to quantitatively assess differences in wake velocity distributions due to wake dissipating devices and span loading changes on the wake-generating model is also demonstrated.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 157-192
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  • 80
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    Effect of compliant wall motion on turbulent boundary layers (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A critical analysis of available wall data which indicated drag reduction under turbulent boundary layers. Detailed structural dynamic calculations suggest the surfaces responded in a resonant, rather than compliant, manner. Alternate explanations are given for drag reductions observed in two classes of experiments: flexible pipe flown, and waterbacked membranes in air. Analysis indicates the wall motion for the remaining data is typified by short wave lengths in agreement with the requirement of a possible compliant wall drag reduction mechanism recently suggested by Langley.
    Keywords: AERODYNAMICS
    Type: AGARD Spec. Course on Concepts for Drag Reduction; 26 p
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  • 81
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    Progress in the development of a Mach 5 quiet tunnel (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Various techniques to control and reduce radiated noise and the application of these techniques to a 1/2-water Mach 5 quiet tunnel are reviewed. Measurements in a small scale nozzle have shown that the upstream part of the supersonic wall boundary layer could be maintained laminar up to Reynolds numbers of nearly 4 x 1 million based on the test region length upstream of the nozzle exit. Turbulent noise levels in this test region were then reduced by an order of magnitude. To maintain low noise levels at higher Reynolds numbers, laminar flow noise shields are required. Data are presented for shields that consist of small diameter rods alined nearly parallel to the entrance flow with small gaps between the rods for boundary layer suction. Analysis and data presented on the noise shielding and reflection characteristics of flat plates and a rod-wall test panel indicate that freestream turbulent noise can be reduced by 70 to 90 deg at high Reynolds numbers. Performance estimates for the 1/2-meter tunnel are based on these results.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AGARD Laminar-Turbulent Transition; 14 p
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  • 82
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    Methods for Reducing Subsonic Drag Due to Lift (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: The results of repeat experimental research on methods for reducing subsonic drag due to lift are discussed. The NASA supercritical airfoils and their application to structurally practical wings with increased aspect radio are described. A design approach and experimental results for wing-tip-mounted winglets are presented. Several methods for utilizing the thrust of jet engines to provide reductions in the drag due to lift are also discussed.
    Keywords: AERODYNAMICS
    Type: AGARD Spec. Course on Concepts for Drag Reduction; 17 p
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  • 83
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    Efficient solution of unsteady transonic flows about airfoils (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: An implicit finite difference procedure was developed for the efficient solution of unsteady transonic flow fields. Sample computations illustrate applications of procedures to aerodynamic problems. Solutions are presented that illustrate three types of shock wave motion that can result from airfoil control surface oscillations. The significant effect of wind tunnel wall conditions on these shock wave motions is demonstrated. Solutions are also presented for a simple aeroelastic problem in which the flow field equations and the structural motion equations are integrated simultaneously in time. Both stable and unstable aeroelastic interactions are considered. The procedure is adapted to compute unsteady aerodynamic force coefficients by the indicial method.
    Keywords: AERODYNAMICS
    Type: AGARD Unsteady Airloads in Separated and Transonic Flow; 11 p
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  • 84
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    Assessment of existing analytic methods for prediction of high angle-of-attack loads on delta wings at supersonic speeds (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: An assessment of the applicability of four loading prediction methods to high angle-of-attack conditions for simplified wing-body configurations is provided. The methods are: The tangent wedge approximation, the linear theory methods of Middleton and Woodward, and a shock-fitting finite-difference technique. Estimates obtained by these methods were compared with experimental pressure data on delta wings to examine the effects of Mach number, camber, sweep angle, and angle of attack. Results indicate that all of the methods provided reasonable estimates at moderate angles of attack. At these moderate angles of attack, the methods of Middleton and Woodward provided good estimates at Mach numbers higher than those usually associated with linear theory. Only the finite-difference method provided reasonable load estimates at high angles of attack.
    Keywords: AERODYNAMICS
    Type: AGARD Prediction of Aerodynamic Loading; 7 p
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  • 85
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    Comparisons of Theoretical and Experimental Pressure Distributions on an Arrow-Wing Configuration at Subsonic, Transonic, and Supersonic Speeds (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A wind tunnel test of an arrow wing body configuration consisting of flat and twisted wings, as well as a variety of leading- and trailing-edge control surface deflection, has been conducted at Mach numbers from 0.40 to 2.50 to provide an experimental data base for comparison with theoretical methods. Theory-to-experiment comparisons of detailed pressure distributions have been made using current state-of-the-art attached- and separated-flow methods. The purpose of these comparisons was to delineate conditions under which these theories are valid for aeroelastic calculations and to explore the use of empirical methods to correct the theoretical methods where theory is deficient. It was determined that current state-of-the-art attached flow and empirical methods were inadequate to predict aeroelastic loads for this configuration.
    Keywords: AERODYNAMICS
    Type: AGARD Prediction of Aerodynamic Loading; 14 p
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  • 86
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    Inviscid modeling of aircraft trailing vortices (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A survey is presented of inviscid theoretical methods that are useful in the study of lift-generated vortices. Concepts derived using these invisicid theories are cited which have helped to guide research directed at alleviating the velocities and rolling moments imposed on aircraft entering these wakes.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 9-60
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  • 87
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    Behavior of fluids in a weightless environment (1977)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Fluid behavior in a low-g environment is controlled primarily by surface tension forces. Certain fluid and system characteristics determine the magnitude of these forces for both a free liquid surface and liquid in contact with a solid. These characteristics, including surface tension, wettability or contact angle, system geometry, and the relationships governing their interaction, are discussed. Various aspects of fluid behavior in a low-g environment are then presented. This includes the formation of static interface shapes, oscillation and rotation of drops, coalescence, the formation of foams, tendency for cavitation, and diffusion in liquids which were observed during the Skylab fluid mechanics science demonstrations. Liquid reorientation and capillary pumping to establish equilibrium configurations for various system geometries, observed during various free-fall (drop-tower) low-g tests, are also presented. Several passive low-g fluid storage and transfer systems are discussed. These systems use surface tension forces to control the liquid/vapor interface and provide gas-free liquid transfer and liquid-free vapor venting.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lyndon B. Johnson Space Center Bioprocessing in Space; p 37-52
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  • 88
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    Unsteady aerodynamic modeling for arbitrary motions (1977)
    In:  Other Sources
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    Publication Date: 2015-11-05
    Description: Results indicating that unsteady aerodynamic loads derived under the assumption of simple harmonic motions executed by airfoil or wing can be extended to arbitrary motions are summarized. The generalized Theodorsen (1953) function referable to loads due to simple harmonic oscillations of a wing section in incompressible flow, the Laplace inversion integral for unsteady aerodynamic loads, calculations of root loci of aeroelastic loads, and analysis of generalized compressible transient airloads are discussed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; Volume 15; Apr. 1977
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  • 89
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    Scanning and focusing mechanisms of METEOSAT radiometer (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The scanning and focusing mechanisms settled onboard the METEOSAT Radiometer are described. A large camera which will take line by line pictures of the earth from a geostationary satellite in the same manner as a TV picture using both the spin of the spacecraft and the tilt of a telescope is included. The scanning mechanism provides the + or - 9 degrees tilt angle of the telescope through 2,500 elementary steps of 1.256 0.0001 radian. As the radiometer image quality is closely dependent on the characteristics of the scanning law, the mechanism is required to fulfill functional performances specifications particularly severe in terms of linearity of the scan curve, accuracy of each step as well as repeatability of the short-term scanning. The focusing mechanism allows + or - 12 millimeters shift of the telescope focus by step increments of 0.140 mm. The focus adjustment is achieved by moving a dihedral reflector according to a pure straight-line motion. The main requirements of each mechanism are summarized and their design and performances are described in detail.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Res. Center The 11th Aerospace Mech. Symp.; p 13-22
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  • 90
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    The development and use of spoilers as vortex attenuators (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Results are presented of groundbased and flight investigations performed to develop spoilers as trailing vortex alleviation devices. Based on the results obtained in these investigations, it was found that the induced rolling moment on a trailing model can be reduced by spoilers located near the midsemispan of a vortex generating wing. Substantial reductions in induced rolling moment occur when the spoiler vortex attenuator is located well forward on both unswept and swept wing models. In addition, it was found that existing flight spoilers on the jumbo-jet transport aircraft can be effective as trailing vortex attenuators.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 339-368
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  • 91
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    Unsuccessful Concepts for Aircraft Wake Vortex Minimization (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Exploratory concepts are described which were investigated to achieve a reduction in the vortex induced rolling upsets produced by heavy aircraft trailing vortexes. The initial tests included the use of mass injection, oscillating devices, wingtip shape design, interacting multiple vortexes, and end plates. Although later refinements of some of these concepts were successful, initial test results did not indicate a capability of these concepts to significantly alter the vortex induced rolling upset on a following aircraft.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 221-250
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  • 92
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    Flight test techniques for wake-vortex minimization studies (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Flight test techniques developed for use in a study of wake turbulence and used recently in flight studies of wake minimization methods are discussed. Flow visualization was developed as a technique for qualitatively assessing minimization methods and is required in flight test procedures for making quantitative measurements. The quantitative techniques are the measurement of the upset dynamics of an aircraft encountering the wake and the measurement of the wake velocity profiles. Descriptions of the instrumentation and the data reduction and correlation methods are given.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 193-220
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  • 93
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    Aircraft wake-vortex minimization by use of flaps (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A survey was made of research on the alleviation of the trailing vortex hazard by altering span loading with flaps on the generator airplane. Flap configurations of the generator that shed multiple vortices were found to have wakes that dispersed by vortex merging and sinusoidal instability. Reductions of approximately 50 percent in both the wake rolling moment imposed on a following aircraft and the aircraft separation requirement were achieved in the ground based and flight test experiments by deflecting the trailing edge flaps more inboard than outboard. Significantly, this configuration did not increase the drag or vibration on the generating aircraft compared to the conventional landing configuration. Ground based results of rolling moment measurement and flow visualization are shown, using a water tow facility, an air tow facility, and a wind tunnel. Flight test results are also shown, using a full scale B-747 airplane. General agreement was found among the results of the various ground based facilities and the flight tests.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 305-338
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  • 94
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    Thrust-augmented vortex attenuation (1977)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An experimental investigation was conducted to determine the vortex attenuating effect of engine thrust. Tests were made using a 0.03-scale model of the Boeing 747 transport aircraft as a vortex generating model. A Learjet-class probe model was used to measure the vortex induced rolling moment at a scale separation distance of 1.63 km. These tests were conducted at a lift coefficient of 1.4 at a model velocity of 30.48 m/s. The data presented indicate that engine thrust is effective as a vortex attenuating device when the engines are operated at high thrust levels and are positioned to direct the high energy engine wake into the core of the vortex. The greatest thrust vortex attenuation was obtained by operating the inboard engine thrust reversers at one-quarter thrust and the outboard engines at maximum forward thrust.
    Keywords: AERODYNAMICS
    Type: Wake Vortex Minimization; p 251-270
    Format: application/pdf
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  • 95
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    Slot injection for skin-friction drag reduction (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A description and analysis of slot injection in low-speed flow, slot injection in high-speed flow, a discussion of aircraft applications, and possibilities for future improvements of slot drag reduction capability are presented.
    Keywords: AERODYNAMICS
    Type: AGARD Spec. Course on Concepts for Drag Reduction; 11 p
    Format: text
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  • 96
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    An overview of concepts for aircraft drag reductions (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A current overview of aerodynamic drag reduction concepts which have potential for reducing aircraft fuel consumption is presented. The discussion shows where the greatest percentages of aircraft fuel is burned and what areas have the greatest potential for fuel conservation. The paper deals with aerodynamic improvements and touches only briefly on structural and propulsion improvements. Concepts for reducing pressure drag (i.e., roughness, wave, interference, and separation drag), drag due to lift/induced drag, and skin-friction drag at subsonic and supersonic speeds are emphasized.
    Keywords: AERODYNAMICS
    Type: AGARD Spec. Course on Concepts for Drag Reduction; 30 p
    Format: text
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  • 97
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    Laminar flow control laminarization (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A practical aerodynamically and structurally reasonably efficient laminar flow control (LFC) suction method, removing the slowest boundary layer particles through many closed spaced fine slots, was developed and subsequently applied to a second F94 LFC wing glove in flight: 100 percent laminar flow was observed up to the F94 test limit. Laminar flow on LFC wings in flight is thus possible at a much higher Reynold's number than even in the best low turbulence tunnels as a result of the negligible influence of the atmospheric microscale turbulence on transition. The F94 LFC glove comparison experiments, with suction starting at 0.03c and 0.4c, verified the theoretically predicted boundary layer stabilization by suction starting at 0.08c, thus maintaining laminar flow at substantially higher C sub L numbers as compared to boundary layer stabilization by flow acceleration; i.e., geometry alone without suction upstream of 0.4c.
    Keywords: AERODYNAMICS
    Type: AGARD Spec. Course on Concepts for Drag Reduction; 75 p
    Format: text
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  • 98
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    Aerodynamic loads near cranks, apexes, and tips of thin, lifting wings in incompressible flow (1977)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: The calculation of the incompressible and irrotational flow in the vicinity of tips and corners of thin, lifting wings is considered. It is shown that the important characteristics of the flow are governed by an eigenvalue problem, which is nonlinear at the trailing edge because of the shed wake (assumed to be in the wing plane). A new solution method was devised because either the existing methods were not valid for the trailing edge case or they would have required excessive amounts of computer time. The new method, which is fundamentally different than the previous ones, was used to calculate solutions for a number of cases, including some for which correct answers had not previously been obtained. Two of these solutions were used to determine the validity of drag and leading-edge-suction distributions near the tips of a delta wing and a swept wing as calculated by using both the vortex lattice method and a kernel function method. The calculations for the swept wing resolved the question of whether or not the induced drag should be zero at the wing tip.
    Keywords: AERODYNAMICS
    Type: AGARD Prediction of Aerodynamic Loading; 12 p
    Format: text
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  • 99
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    The calculation of the mass moment of inertia of a fluid in a rotating rectangular tank (1977)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This analysis calculated the mass moment of inertia of a nonviscous fluid in a slowly rotating rectangular tank. Given the dimensions of the tank in the x, y, and z coordinates, the axis of rotation, the percentage of the tank occupied by the fluid, and angle of rotation, an algorithm was written that could calculate the mass moment of inertia of the fluid. While not included in this paper, the change in the mass moment of inertia of the fluid could then be used to calculate the force exerted by the fluid on the container wall.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-CR-197777 , NAS 1.26:197777
    Format: application/pdf
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  • 100
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    Experimental studies of flow separation of the GA(W)-2 airfoil at low speeds (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Wind tunnel tests have been conducted on a NASA GA(W)-2 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 10.3, 14.4, and 18.3 deg. 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 lower 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-197254 , NAS 1.26:197254 , AR77-4
    Format: text
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