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  • AERODYNAMICS  (419)
  • FLUID MECHANICS AND HEAT TRANSFER  (362)
  • 42.75
  • 1995-1999
  • 1980-1984  (781)
  • 1950-1954
  • 1982  (781)
Collection
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  • 1995-1999
  • 1980-1984  (781)
  • 1950-1954
Year
  • 1
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    In-flight lift and drag measurements on a first generation jet transport equipped with winglets (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A KC-135A aircraft equipped with wing tip winglets was flight tested to demonstrate and validate the potential performance gain of the winglet concept as predicted from analytical and wind tunnel data. Flight data were obtained at cruise conditions for Mach numbers of 0.70, 0.75, and 0.80 at a nominal altitude of 36,000 ft. and winglet configurations of 15 deg cant/-4 deg incidence, 0 deg cant/-4 deg incidence, and baseline. For the Mach numbers tested the data show that the addition of winglets did not affect the lifting characteristics of the wing. However, both winglet configurations showed a drag reduction over the baseline configuration, with the best winglet configuration being the 15 deg cant/-4 deg incidence configuration. This drag reduction due to winglets also increased with increasing lift coefficient. It was also shown that a small difference exists between the 15 deg cant/-4 deg incidence flight and wind tunnel predicted data. This difference was attributed to the pillowing of the winglet skins in flight which would decrease the winglet performance.
    Keywords: AERODYNAMICS
    Type: KC-135 Winglet Program Rev.; p 103-116
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  • 2
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    KC-135 winglet program overview (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A joint NASA/USAF program was conducted to accomplish the following objectives: (1) evaluate the benefits that could be achieved from the application of winglets to KC-135 aircraft; and (2) determine the ability of wind tunnel tests and analytical analysis to predict winglet characteristics. The program included wind-tunnel development of a test winglet configuration; analytical predictions of the changes to the aircraft resulting from the application of the test winglet; and finally, flight tests of the developed configuration. Pressure distribution, loads, stability and control, buffet, fuel mileage, and flutter data were obtained to fulfill the objectives of the program.
    Keywords: AERODYNAMICS
    Type: KC-135 Winglet Program Rev.; p 1-46
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  • 3
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    KC-135 wing and winglet flight pressure distributions, loads, and wing deflection results with some wind tunnel comparisons (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A full-scale winglet flight test on a KC-135 airplane with an upper winglet was conducted. Data were taken at Mach numbers from 0.70 to 0.82 at altitudes from 34,000 feet to 39,000 feet at stabilized flight conditions for wing/winglet configurations of basic wing tip, 15/-4 deg, 15/-2 deg, and 0/-4 deg winglet cant/incidence. An analysis of selected pressure distribution and data showed that with the basic wing tip, the flight and wind tunnel wing pressure distribution data showed good agreement. With winglets installed, the effects on the wing pressure distribution were mainly near the tip. Also, the flight and wind tunnel winglet pressure distributions had some significant differences primarily due to the oilcanning in flight. However, in general, the agreement was good. For the winglet cant and incidence configuration presented, the incidence had the largest effect on the winglet pressure distributions. The incremental flight wing deflection data showed that the semispan wind tunnel model did a reasonable job of simulating the aeroelastic effects at the wing tip. The flight loads data showed good agreement with predictions at the design point and also substantiated the predicted structural penalty (load increase) of the 15 deg cant/-2 deg incidence winglet configuration.
    Keywords: AERODYNAMICS
    Type: KC-135 Winglet Program Rev.; p 47-102
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  • 4
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    Full-coverage film cooling (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Transpiration cooling is treated and then full coverage discrete hole injection for three injection orientations. Spacings with pitch to diameter ratios of 5 and 10 are discussed. The array is staggered, with the transverse pitch and the streamwise pitch the same. Results are presented in terms of the Stanton number using the heat transfer coefficient defined in terms of the difference between the wall temperature and the free stream temperature. Two values of Stanton number are provided for each situation: one with the injectant at wall temperature, and the other with the injectant at free stream temperature. These two values are equivalent to knowing the heat transfer coefficient and the adiabatic effectiveness. The heat transfer coefficient thus defined is used with the actual wall temperature to and the actual gas temperature to calculate the heat load. The principle of superposition thus invoked is valid exactly when the governing equations are linear.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Von Karman Inst. for Fluid Dyn. Film Cooling and Turbine Blade Heat Transfer, Vol. 1; 27 p
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  • 5
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    Heat loss and drag of spherical drop tube samples (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Analysis techniques for three aspects of the performance of the NASA/MSFC 32 meter drop tube are considered. Heat loss through the support wire in a pendant drop sample, temperature history of a drop falling through the drop tube when the tube is filled with helium gas at various pressures, and drag and resulting g-levels experienced by a drop falling through the tube when the tube is filled with helium gas at various pressures are addressed. The developed methods apply to systems with sufficiently small Knudsen numbers for which continuum theory may be applied. Sample results are presented, using niobium drops, to indicate the magnitudes of the effects. Helium gas at one atmosphere pressure can approximately double the amount of possible undercooling but it results in an apparent gravity levels of up to 0.1 g.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: the 1981 NASA(ASEE Summer Fac. Fellowship Program; 31 p
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  • 6
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    Turbulent boundary layer heat transfer (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Several environmental parameters presently acknowledged to affect heat transfer are discussed including: (1) the experimental apparatus used, (2) uniform and variable wall temperatures, (3) acceleration effects, (4) deceleration, (5) free stream turbulence, (6) surface roughness, (7) unsteady effects, and (8) secondary flows. Calculation procedures, and some physically based models that are successful in computing heat transfer rates are discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Von Karman Inst. for Fluid Dyn. Film Cooling and Turbine Blade Heat Transfer, Vol. 1; 40 p
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  • 7
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    Curvature effects and turbulent boundary layers (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Results are examined from an experiment conducted to determine quantitatively the secondary factors which affect the response of a turbulent boundary layer to convex curvature and to examine the recovery process after curvature ended. The variation of Stanton number with streamwise distance and with enthalpy thickness Reynolds number for the baseline case is shown. The effect of delta sub .99/R on the velocity of the potential core would have if we extended to the wall with no viscous effects, of free stream acceleration, of an unheated starting length, and of boundary layer maturity are discussed. Mixing length and turbulent Prandtl number models are reviewed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Von Karman Inst. for Fluid Dyn. Film Cooling and Turbine Blade Heat Transfer, Vol. 1; 29 p
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  • 8
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    Analysis of the decay of temperature fluctuations in isotropic turbulence (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The Lagrangian dispersion theory of Durbin (1980) is used to analyze experiments by Warhaft and Lumley (1978) and by Sreenivasan et al. (1980) on temperature fluctuations in grid-generated turbulence. Both theory and experiment show that the decay exponent m depends on the ratio of the initial length scales of velocity and temperature, although when this ratio is greater than 2.5 such dependence is negligible. The theory shows that m is not truly constant, but within the range covered by the experiments it is nearly so. The agreement between theory and experiment lends credence to the idea that the decay of fluctuations is controlled largely by turbulent relative dispersion.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids; 25; Aug. 198
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  • 9
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    Turbulence amplification in shock-wave boundary-layer interaction (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Attention is directed to the acoustics research of the 1950s and 1960s for guidance in understanding and quantizing the turbulence amplification that can occur in regions of shock-wave boundary-layer interaction. Three primary turbulence amplifier-generator mechanisms are identified and shown, by linear analysis, to be responsible for turbulence amplification across a shock wave in excess of 100% of the incident turbulence intensity.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; July 198
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  • 10
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    Axisymmetric inviscid swirling flows produced by bellmouth and centerbody (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The effect of large deformation in the flow between the bellmouth and centerbody is considered analytically for application to studies of vortex breakdown in a pipe. Basic equations are defined for axisymmetric inviscid swirling flows at the inflow and outflow sections. Axial and circumferential velocity component profiles are presented, and comparisons are made with trials involving vane angles of 42 deg and Re of 2300. Axial components of the prediction matched well in the inner half of the pipe radius and not well with the outer, while circumferential predictions were good only at the axis. A lack of viscosity was concluded to result in the inaccuracies near the wall.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 20; Apr. 198
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  • 11
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    SPF/DB titanium concepts for structural efficiency foi HC (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Illustrations for a presentation on superplastic forming/diffusion bonding titanium design concepts are presented. Sandwich skin panels with hat section, semicircular corrugation, sine wave, and truss cores are shown. The fabrication of wing panels is illustrated, and applications to the design of advanced variable sweep bombers summarized.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Laminar Flow Control; p 95-110
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  • 12
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    SPF/DB titanium LFC porous panel concept (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Illustrations for a presentation demonstrating superplastic forming/diffusion bonding titanium porous panels are presented. Fabrication phases, sandwich panels, load bearing qualities, microstructure, and panel surface after finishing are illustrated.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Laminar Flow Control; p 111-138
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  • 13
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    X-29A forward-swept-wing demonstrator airplane (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The X-29A is a technology demonstrator. The FSW is just one of the technologies. Others include the following: discrete variable camber, relaxed static stability, triplex digital fly-by-wire (FBW) control system, variable-incidence/close-coupled canard, aeroelastically tailored composite wing, and thin supercritical airfoil. The growth potential for additional technologies is shown.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 177-189
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  • 14
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    Opportunities for wind-tunnel/flight correlation with new Boeing airplanes (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The use of correlated data in airplane development is discussed. Areas of interest include initial airworthiness of an aircraft, low-speed configuration optimization, and high-speed configuration optimization. Data from wind tunnel tests are shown to be significant when applied to guarantee compliance, which includes fuel consumption, airspeeds, and takeoff and landing performance. The use of correlation in achieving FAA certification is also discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel-Flight Correlation, 1981; p 141-157
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  • 15
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    F-15 wind-tunnel/flight correlations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: F-15 correlation data for longitudinal control and inlet-ramp effectiveness, and horizontal-tail setting for trim are presented. The Reynolds number effect on airfoil laminar bubble burst is included.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 109-115
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  • 16
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    Wind-tunnel/flight correlation program on XB-70-1 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The XB-70-1 was selected for a wind-tunnel/flight correlation program as representative of a large, flexible supersonic airplane similar to a supersonic transport. Tests were made to determine the effects of control deflections, wing tip deflection, and variations in inlet mass flow (additive drag).
    Keywords: AERODYNAMICS
    Type: Wind-Tunnel(Flight Correlation, 1981; p 65-91
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  • 17
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    X-29A for NTF wind-tunnel/flight correlations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Considerations and recommendations for correlation are given. Basic tunnel calibration prior to research and development tests is suggested. Areas of concentration include: wing cruise drag and drag rise, wing separation and stall, afterbody and base drag, propulsion effects, vortex flows, cavity flows, and excrescences.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 191-197
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  • 18
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    Space-vehicle correlation of ground and flight experiments (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A 2-percent-scale model was designed for testing in the NTF. This model has remotely controlled elevons, body flap, and rudder to minimize tunnel entries associated with configuration changes in the NTF. The Shuttle Orbiter has a very large aerodynamic data base obtained in ground facilities. Since the vehicle flight-test program has already begun, a large amount of flight data can be analyzed and correlated with the NTF results.
    Keywords: AERODYNAMICS
    Type: Wind-Tunnel(Flight Correlation, 1981; p 173-176
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  • 19
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    Aerodynamic comparisons of Space Shuttle ascent: STS-1 flight versus wind-tunnel predictions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is found from the comparisons that large longitudinal aerodynamic differences exist between wind tunnel predictions and flight measurements. Cold gas plume simulation underpredicted Shuttle base pressure. It is concluded that observed flight prediction increments are probably caused by several factors such as input error, independent variable errors, plume effects, and Reynolds number effects.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 133-140
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  • 20
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    Problems in correlation caused by propulsion systems (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Correlation efforts and selected results for transonic drag are reviewed. A process to reduce the typical error sources to decrease the errors inherent in the transonic aircraft development process is summarized.
    Keywords: AERODYNAMICS
    Type: Wind-Tunnel(Flight Correlation, 1981; p 93-108
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  • 21
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    Wind-tunnel/flight-drag correlation (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Predicted and flight-test drag on the C-5A and the C-141 are correlated. Equivalent rigid flight-test profile drag and a rigid estimate based on wind tunnel data are also correlated. Correlations for the National Transonic Facility are included.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 33-46
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  • 22
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    Review of the 1980 Wind-Tunnel/Flight Correlation Panel (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Wind tunnel/flight correlation history from the P-51 to the F-8 supercritical wing is reviewed, showing that researchers continue to be faced with nearly identical discrepancies in predicted versus measured drag. The capabilities of the National Transonic Facility to allow assessment of the effects which have heretofore plagued researchers and aircraft designers are anticipated.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 23-32
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  • 23
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    Transonic-flow computation using an explicit-implicit method (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The explicit-implicit predictor corrector method of MacCormack (1981) is applied to the analysis of flows past airfoils. By comparing results obtained with different methods and meshes, it is shown that the above method provides, after certain modifications, reasonably good predictions of inviscid and viscous flows about an airfoil. Good results are also obtained for the transonic regime if the free-stream conditions are correct and if a suitable mesh is used.
    Keywords: AERODYNAMICS
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  • 24
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    Study of incompressible turbulent channel flow by large eddy simulation (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Incompressible turbulent channel flow is investigated by large eddy simulation using improved numerical methods and boundary conditions. In downstream and spanwise directions, cyclic boundary conditions are imposed for velocity and pressure, and two types of boundary conditions near the wall are used and compared. One type is based on the logarithmic law of the mean velocity near the wall and has a slip boundary condition where the molecular-viscous term is neglected. The other type is based on a no-slip boundary condition, where fine mesh spacing near the wall is used to take account of the molecular viscosity. Although the present study employs a coarse mesh (16 x 16 x 21), its results are in good agreement with those of Moin and Kim (1981).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 25
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    Developing flow in S-shaped ducts (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The velocity characteristics of laminar and turbulent developing flow in an S-duct formed from two 22.5-deg bends of rectangular cross-section have been studied experimentally using laser Doppler velocimetry. It is shown that pressure-driven secondary flows arise in the first bend of the duct and reach maxima of 0.22 and 0.15 of the bulk velocity in the laminar and turbulent flows, respectively. The velocities are greater in the laminar flow, mainly because of the thicker inlet boundary layers. On passing through the second half of the S-duct, a secondary flow is established over most of the section in the direction opposite to that in the first half. Near the outer wall of the second bend, however, the secondary flow generated in the first bend is sustained because of the local sign of radial vorticity. This effect contributes to a redistribution of the streamwise isotachs, by the end of the duct, comparable with that in unidirectional bends.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 26
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    Stability of erythrocyte suspensions layered on stationary and flowing liquids (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The apparent stability of erythrocyte suspensions layered on stationary and flowing Ficoll solutions was studied considering the effects of particle concentration, type and size, and the different flow rates of the particle suspensions and chamber liquid. The data from the flowing system were empirically fitted and, when extrapolated to zero chamber liquid flow rate, gave values comparable to the data from the stationary system, thus confirming the validity of the data and our approach to obtain that data.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Separation Science and Technology; 17; 6, 19; 1982
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  • 27
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    On the impingement of supersonic jet on a normal flat surface (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An improved method, based on one strip approximation of the method of integral relations which was reported originally by Belov, Ginzburg and Shub (1973), is presented for the calculation of flow parameters in the impingement region of a supersonic, underexpanded jet striking a normal surface located within the first cell. The results are presented for two impingement conditions and found to be in good agreement with the experimental data.
    Keywords: AERODYNAMICS
    Type: Aeronautical Quarterly; 33; Aug. 198
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  • 28
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    Pressure distributions and shock shapes for a bent-nose biconic at incidence (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Initial results of a NASA study of the lift-drag characteristics of a 12.84/7 deg biconic model intended for airbraking during atmospheric entry of probes to Mars, Venus, Saturn, and Titan are reported. Pressure distributions and shock shapes were measured in the Langley 20 in. Mach 6 tunnel with the spherically blunted bent-nose model set at angles from 0-25 deg. Pressure distributions and shock shapes where computed using the STEIN flowfield code, which features a MacCormack scheme to integrate the three-dimensional Euler equations, the Rankine-Hugoniot jump conditions to model shock waves as discontinuities, and requires a supersonic condition at every step. A comparison was made between measured and predicted values. The leeward shock angle was found to be predictable to within 3% for all angles of attack, while parabolized Navier-Stokes equations are regarded as offering more accurate results than the STEIN code for surface pressure distributions.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Aug. 198
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  • 29
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    Chordwise and compressibility corrections for arbitrary planform slender wings (1982)
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    Publication Date: 2011-08-18
    Description: The Lomax and Sluder method for adapting slender-wing theory to delta or rectangular wings by making chordwise and compressibility corrections is extended to cover wings of any arbitrary planform in subsonic and supersonic flows. The numerical accuracy of the present work is better than that of the Lomax-Sluder results. Comparison of the results of this work with those of the vortex-lattice method and Kernel function method for a family of Gothic and arrowhead wings shows good agreement. A universal curve is proposed for the evaluation of the lift coefficient of a low aspect ratio wing of an arbitrary planform in subsonic flow. The location of the center of pressure can also be estimated.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Aug. 198
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  • 30
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    Numerical investigation of turbulent channel flow (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N81-30385)
    Keywords: AERODYNAMICS
    Type: Journal of Fluid Mechanics; 118; May 1982
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  • 31
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    Wind-tunnel wall interference corrections for three-dimensional flows (1982)
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    Publication Date: 2011-08-18
    Description: A procedure for the evaluation of wall interference corrections for three-dimensional aircraft configurations is presented. The Mach number and angle-of-attack corrections are obtained by numerically solving the Laplace equation in a parallelepiped with boundary conditions supplied mainly from experimental pressure measurements. A portion of these measurements and other wind-tunnel data required by the procedure may be replaced by theoretical estimates if not available from experiments. The accuracy of the correction results will then depend on the accuracy of these estimates. The correction procedure is applied to an isolated wing and to a wing-tail configuration in a solid-wall wind tunnel. It is found that neglecting twist and camber corrections for the wing effectively increases the tail angle-of-attack correction. Two different Mach number corrections can be calculated for the wing and tail. However, since only one Mach number correction is allowed for both the wing and the tail, and since the wing surface area is larger than the tail surface area, the final correction tends to be closer to the required wing correction. This is a source of error for the tail results.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 19; June 198
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  • 32
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    Validation of LTRAN2-HI by comparison with unsteady transonic experiment (1982)
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N81-29092)
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; May 1982
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  • 33
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    Cauchy integral method for two-dimensional solidification interface shapes (1982)
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    Publication Date: 2011-08-18
    Description: A method is developed to determine the shape of steady state solidification interfaces formed when liquid above its freezing point circulates over a cold surface. The solidification interface, which is at uniform temperature, will form in a shape such that the non-uniform energy convected to it is locally balanced by conduction into the solid. The interface shape is of interest relative to the crystal structure formed during solidification; regulating the crystal structure has application in casting naturally strengthened metallic composites. The results also pertain to phase-change energy storage devices, where the solidified configuration and overall heat transfer are needed. The analysis uses a conformal mapping technique to relate the desired interface coordinates to the components of the temperature gradient at the interface. These components are unknown because the interface shape is unknown. A Cauchy integral formulation provides a second relation involving the components, and a simultaneous solution yields the interface shape.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer; 25; July 198
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    Calculation of radiation from argon shock layers (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The accuracy of calculations of the radiation emissions from argon plasmas produced by the shock layers over blunt bodies is assessed. The existing theoretical and experimental spectroscopic data on argon are collated. A set of such data is selected for use in the radiative transfer calculations. Calculations are performed for the stagnation regions of the shock layers over laboratory-sized models using these data, and the results are compared with the existing experimental results obtained in a shock-tube. Through this comparison and a parametric study it is shown that radiative heat fluxes at the stagnation point in an argon environment can be calculated within an uncertainty of about 15%. It is shown also that radiative heat fluxes of the order of 100 kW/sq cm can be produced in the existing laboratory facilities.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer; 28; July 198
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  • 35
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    Large scale model measurements of airframe noise using cross-correlation techniques (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Cross-correlation techniques are used to measure the sound radiated by wing/flap airfoil configurations in the NASA-Ames 40 x 80 ft wind tunnel using a 6.7-m semispan model with three deployed flaps. The dominant source of flap noise is identified as the flap side edges, which exceeds that radiated by the midspan region by more than 10 dB. The turbulent surface eddies at the flap side edge have scales on the order of one-half the flap chord. The installation of flap actuator fairings at the flap side edge reduces the noise radiated from that location by 10 to 15 dB. The cross-correlation technique extracts airframe noise radiated by specific surface locations from the tunnel background noise, even when the noise is 25 dB higher than the measured airframe noise level.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 71
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  • 36
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    Topological analysis of computed three-dimensional viscous flow fields (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Computed solutions of the time-dependent, Reynolds-averaged Navier-Stokes equations for three-dimensional flows having thin shear layers are analyzed, using topological concepts. Specific examples include the transonic flow over a body of revolution with conical afterbody at moderate angles of incidence to the free stream. Experimental flow-visualization techniques are simulated graphically to visualize the computed flow. Scalar and vector fluid dynamic properties, such as pressure, shear stress, and vorticity on the body surface, are presented as topological maps, and their relationship to one another in terms of orientation and singular points is discussed. The extrapolation from these surface topologies toward the understanding of external flow-field behavior is discussed and demonstrated.
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  • 37
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    KC-135A Winglet Flight Flutter Program (1982)
    In:  CASI
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    Publication Date: 2014-09-11
    Description: The evaluation techniques, results and conclusions for the flight flutter testing conducted on a KC-135A airplane configured with and without winglets are discussed. Test results are presented for the critical symmetric and antisymmetric modes for a fuel distribution that consisted of 10,000 pounds in each wing main tank and empty reserve tanks. The results indicated that a lightly damped oscillation was experienced for a winglet configuration of a 0 deg cant and -4 deg incidence. The effects of cant and incidence angle variation on the critical modes are also discussed. Lightly damped oscillations were not encountered for any other winglet cant and incidence angles tested.
    Keywords: AERODYNAMICS
    Type: NASA. Dryden Flight Research Facility KC-135 Winglet Program Rev.; p 171-188
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  • 38
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    Comparison of Flight Measured, Predicted and Wind Tunnel Measured Winglet Characteristics on a KC-135 Aircraft (1982)
    In:  CASI
    Details
    Publication Date: 2014-09-11
    Description: One of the objectives of the KC-135 Winglet Flight Research and Demonstration Program was to obtain experimental flight test data to verify the theoretical and wind tunnel winglet aerodynamic performance prediction methods. Good agreement between analytic, wind tunnel and flight test performance was obtained when the known differences between the tests and analyses were accounted for. The flight test measured fuel mileage improvements for a 0.78 Mach number was 3.1 percent at 8 x 10(5) pounds W/delta and 5.5 percent at 1.05 x 10(6) pounds W/delta. Correcting the flight measured data for surface pressure differences between wind tunnel and flight resulted in a fuel mileage improvement of 4.4 percent at 8 x 10(5) pounds W/delta and 7.2 percent at 1.05 x 10(6) pounds W/delta. The performance improvement obtained was within the wind tunnel test data obtained from two different wind tunnel models. The buffet boundary data obtained for the baseline configuration was in good agreement with previous established data. Buffet data for the 15 deg cant/-4 deg incidence configuration showed a slight improvement, while the 15 deg cant/-2 deg incidence and 0 deg cant/-4 deg incidence data showed a slight deterioration.
    Keywords: AERODYNAMICS
    Type: NASA. Dryden Flight Research Facility KC-135 Winglet Program Rev.; p 145-170
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  • 39
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    Resonant entrainment of a confined pulsed jet (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper reports the discovery of a new resonant entrainment phenomenon associated with a confined, pulsed jet flow. It was found that a confined jet, when pulsed at an organ-pipe resonant frequency of the confinement tube, experiences greatly enhanced entrainment and mixing near the exit end of the confinement tube compared to a steady confined jet. The mixing and entrainment rates for the resonantly pulsed confined jet approach, and in some cases slightly exceed, those for an unconfined pulsed jet. Both visual and quantitative evidence of this phenomenon is presented. The new effect should be of considerable interest in ejector and combustor design, both of which benefit from any enhancement in mixing between a primary and a secondary flow
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 40
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    Use of thermocapillary migration in a controllable heat valve (1982)
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    Publication Date: 2011-08-18
    Description: In accordance with the Marangoni effect, immiscible droplets in a host fluid in which a temperature gradient exists move in the direction of increasing temperature. It is proposed that this thermocapillary migration could be used to construct a 'liquid wick' that would return the condensed vapor at the condenser end of a heat pipe back to the evaporator, thus completing the fluid circuit. The droplets would be formed by capillary pressure forcing the condensate through a perforated diaphragm whose temperature would control the droplet flux, and hence the heat flux between the two ends of the heat pipe, thus making it a controllable heat valve.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Applied Physics; 53; Dec. 198
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  • 41
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    Determination of boundary shape of cooled porous region (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The shape of a cooled porous wall section is found that will provide a uniform surface temperature, as dictated by material limitations, when the surface is subjected to spatially nonuniform heating. In the analysis, local temperatures and pressures in the porous material are expressed in terms of a potential function. From the imposed thermal conditions, this potential function is governed by the dual constraints of both its value and its normal derivative being specified along the heated surface. The unknown shape of this surface is obtained by meeting these dual conditions. The analytical method uses a generalized conformal mapping procedure that includes a curved boundary. The coolant flow can be compressible or incompressible, and its viscosity can depend on temperature.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 42
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    Status of NASA advanced LFC airfoil high-lift study (1982)
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    Publication Date: 2011-08-18
    Description: The design of a high lift system for the NASA advanced LFC airfoil designed by Pfenninger is described. The high lift system consists of both leading and trailing edge flaps. A 3 meter semispan, 1 meter chord wing model using the above airfoil and high lift system is under construction and will be tested in the NASA Langley 4 by 7 meter tunnel. This model will have two separate full span leading edge flaps (0.10c and 0.12c) and one full span trailing edge flap (0.25c). The performance of this high lift system was predicted by the NASA two dimensional viscous multicomponent airfoil program. This program was also used to predict the characteristics of the LFC airfoils developed by the Douglas Aircraft Company and Lockheed-Georgia Aircraft Company.
    Keywords: AERODYNAMICS
    Type: Laminar Flow Control; p 43-62
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  • 43
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    NASA Langley laminar flow control airfoil experiment (1982)
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    Publication Date: 2011-08-18
    Description: The design and construction of an advanced swept supercritical airfoil for commercial aircraft to be tested in a transonic wind tunnel is described. The swept LFC airfoil was designed for a given thickness ratio and lift coefficient, with emphasis placed on high critical Mach number with shock-free flow. It is compatible with satisfactory low speed and buffeting characteristics and minimizing the suction laminarization. Further emphasis was placed on achieving shock-free flow over a wide range of off-design conditions including trailing edge flap control. The requirements and design of the suction system and modifications to the Langley 8 foot transonic pressure tunnel is briefly described. Contouring of nonporous test section walls for free air simulation and flow quality improvements is included.
    Keywords: AERODYNAMICS
    Type: Laminar Flow Control; p 1-42
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  • 44
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    Application of Computational Fluid Dynamics (CFD) in transonic wind-tunnel/flight-test correlation (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The capability for calculating transonic flows for realistic configurations and conditions is discussed. Various phenomena which were modeled are shown to have the same order of magnitude on the influence of predicted results. It is concluded that CFD can make the following contributions to the task of correlating wind tunnel and flight test data: some effects of geometry differences and aeroelastic distortion can be predicted; tunnel wall effects can be assessed and corrected for; and the effects of model support systems and free stream nonuniformities can be modeled.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 199-215
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  • 45
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    Probability of laminar flow loss because of ice crystal encounters (1982)
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    Publication Date: 2011-08-18
    Description: A method for combining the cloud detector observation results from the Global Atmospheric Sampling Program (GASP) with Knollenberg probe observations of cloud particle concentration from other programs to derive estimates of the ambient concentration of particles larger than a given size was developed. The method was applied to estimate the probability of encountering particle concentrations which would degrade the performance of laminar flow control (LFC) aircraft. It is concluded that LF loss should occur only about one percent of the time in clear air and that flight within clouds should always result in a significant loss of LF, with 90 percent LF loss occurring about one percent of the time. Preliminary estimates of cloud encounter probability are presented for four airline routes, and conclusions are presented as to the best altitudes for cloud avoidance in extratropical and tropical latitudes.
    Keywords: AERODYNAMICS
    Type: Laminar Flow Control; p 75-94
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  • 46
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    Some ideas and opportunities concerning three-dimensional wind-tunnel wall corrections (1982)
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    Publication Date: 2011-08-18
    Description: Opportunities for improving the accuracy and reliability of wall corrections in conventional ventilated test sections are presented. The approach encompasses state-of-the-art technology in transonic computational methods combined with the measurement of tunnel-wall pressures. The objective is to arrive at correction procedures of known, verifiable accuracy that are practical within a production testing environment. It is concluded that: accurate and reliable correction procedures can be developed for cruise-type aerodynamic testing for any wall configuration; passive walls can be optimized for minimal interference for cruise-type aerodynamic testing (tailored slots, variable open area ratio, etc.); monitoring and assessment of noncorrectable interference (buoyancy and curvature in a transonic stream) can be an integral part of a correction procedure; and reasonably good correction procedures can probably be developd for complex flows involving extensive separation and other unpredictable phenomena.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 217-229
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  • 47
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    F-16E program overview and wind tunnel/flight correlation (1982)
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    Publication Date: 2011-08-18
    Description: Correlation is defined in three different ways: comparisons of wind tunnel and/or theory with flight results; detailed studies of total vehicle drag from wind tunnel and flight tests; and attempts to understand the fundamental mechanisms of fluid flows associated with aircraft components in specific areas of the flight environment. The F-16E configuration is an outgrowth of studies conducted to produce a refined fighter wing design. Several iterations required to arrive at the combination of wing planform, camber, and twist which gives near optimum lift, drag, and high-angle-of-attack stability. Theoretical analyses were backed up by extensive experimental data to validate the design and are presented
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 159-172
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  • 48
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    Aerodynamic comparisons of STS-1 Space Shuttle entry vehicle (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A conventional flight-test program, which slowly and cautiously approaches more severe flight conditions, was not possible with the Orbiter. On the first flight, the Orbiter entered the atmosphere at Mach 28 and decelerated through the Mach range. (The subsonic portion of flight was also flown by another orbiter vehicle during the Approach and Landing Test Program.) Certification for the first flight was achieved by an extensive wind-tunnel test and analysis program and by restricting the flight maneuvers severely. The initial flights of the orbiter were heavily instrumented for the purpose of obtaining accurate aerodynamic data. Even without maneuvers to excite the system, the first flight provided comparisons between flight and wind-tunnel-derived predicted data in the areas of aerodynamic performance, longitudinal trim, and reaction-control jet interaction. The aerodynamic performance comparisons are presented.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 117-131
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  • 49
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    Tunnel-to-tunnel correlation (1982)
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    Publication Date: 2011-08-18
    Description: Flow quality is discussed. Incremental comparisons of: (1) the angle of attack, (2) the axial force coefficient, and (3) the base cavity axial force coefficient against the normal force coefficient are presented. Relative blockage determination, relative buoyancy corrections, and boundary layer transition length are discussed. Blockage buoyancy caused by tunnel model wall dynamic interaction is discussed in terms of adaptive walls. The effect of 'transonic turbulence factor' is considered.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Wind-Tunnel(Flight Correlation, 1981; p 47-63
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  • 50
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    Numerical simulation of steady supersonic flow over spinning bodies of revolution (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A recently reported parabolized Navier-Stokes code has been employed to compute the supersonic flowfield about a spinning cone and spinning and nonspinning ogive cylinder and boattailed bodies of revolution at moderate incidence. The computations were performed for flow conditions where extensive measurements for wall pressure, boundary-layer velocity profiles, and Magnus force had been obtained. Comparisons between the computational results and experiment indicate excellent agreement for angles of attack up to 6 deg. At angles greater than 6 deg discrepancies are noted which are tentatively attributed to turbulence modeling errors. The comparisons for Magnus effects show that the code accurately predicts the effects of body shape for the selected models.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Dec. 198
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  • 51
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    Numerical study of flowfields about asymmetric external conical corners (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 17, p. 3111, Accession no. A80-41562)
    Keywords: AERODYNAMICS
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  • 52
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    Wall interference evaluation from pressure measurements on control surfaces (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Conventional methods for the calculation of wall interference corrections are based on boundary conditions which require a knowledge of ventilated wall porosity parameters, and which are unsuitable for deformed walls. The method described uses a simple exponential decay of pressure distribution beyond the most upstream and downstream limits in order to evaluate Mach number and incidence corrections given by the method proposed by Papelier et al. (1978). It is found that, while the upstream contribution to incidence correction is significant, the upstream and downstream contributions to Mach number correction are negligible.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 19; Dec. 198
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  • 53
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    Airframe effects on a top-mounted fighter inlet system (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 07, p. 963, Accession no. A82-19212)
    Keywords: AERODYNAMICS
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  • 54
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    Spouts in a bed of silica powder associated with fluidization by outgassing of adsorbed water (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Multiphase Flow; 8; 4, 19; 1982
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  • 55
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    On current aspects of finite element computational fluid mechanics for turbulent flows (1982)
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    Publication Date: 2011-08-18
    Description: A set of nonlinear partial differential equations suitable for the description of a class of turbulent three-dimensional flow fields in select geometries is identified. On the basis of the concept of enforcing a penalty constraint to ensure accurate accounting of ordering effects, a finite element numerical solution algorithm is established for the equation set and the theoretical aspects of accuracy, convergence and stability are identified and quantized. Hypermatrix constructions are used to formulate the reduction of the computational aspects of the theory to practice. The robustness of the algorithm, and the computer program embodiment, have been verified for pertinent flow configurations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    An analytical approach to thermal modeling of Bridgman-type crystal growth. I - One-dimensional analysis (1982)
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    Publication Date: 2011-08-18
    Description: A relatively simple one-dimensional thermal model of the Bridgman growth process has been developed which is applicable to the growth of small diameter samples with conductivities similar to those of metallic alloys. The heat flow in a translating rod is analyzed in a way that is applicable to Biot numbers less than unity. The model accommodates an adiabatic zone, different heat transfer coefficients in the hot and cold zones, and changes in sample material properties associated with phase change. The analysis is applied to several simplified cases. The effect of the rod's motion is studied in a three-zone furnace for a rod sufficiently long that end effects can be neglected; end effects are then investigated for a motionless rod. Finally, the addition of a fourth zone, an independently controlled booster heater between the main heater and the adiabatic zone, is evaluated for its ability to increase the gradient in the sample at the melt interface and to control the position of the interface.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Crystal Growth; 58; 1982
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  • 57
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    The velocity field induced by a helical vortex filament (1982)
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    Publication Date: 2011-08-18
    Description: An exact analytical solution for the velocity field, both interior and exterior, induced by an infinite right-handed helical vortex filament is derived. Due to the way the variables combine in this solution, the paper also shows that it is possible to derive a stream function for this nonaxisymmetric flow. Sample calculations of these expressions are included.
    Keywords: AERODYNAMICS
    Type: Physics of Fluids; 25; Nov. 198
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  • 58
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    Curved ducts with strong secondary motion - Velocity measurements of developing laminar and turbulent flow (1982)
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    Publication Date: 2011-08-18
    Description: Two orthogonal components of velocity and associated Reynolds stresses are determined in a square-sectioned, 90 degree bend of 2.3 radius ratio by utilizing laser-Doppler velocimetry for Reynolds numbers of 790 and 40,000. Results show that boundary layers at the bend inlet of 0.25 and 0.15 of the hydraulic diameter create secondary velocity maxima of 0.6 and 0.4 of the bulk flow velocity, respectively. It is concluded that the boundary layer thickness is important to the flow development, mainly in the first half of the bend, especially when it is reduced to 0.15 of the hydraulic diameter. Smaller secondary velocities are found for turbulent flow in an identical duct with a radius ratio of 7.0 than in the strongly curved bend, although their effect is more important to the streamwise flow development because of the smaller pressure gradients. In addition, the detail and accuracy of the measurements make them suitable for evaluation of numerical techniques and turbulence models.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 59
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    Three-dimensional shock structure in a transonic flutter cascade (1982)
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    Publication Date: 2011-08-18
    Description: Rapid double-pulse holography was employed to obtain detailed, two-dimensional images of the shock forming during simulated flutter in a transonic flowfield. The experiment comprised a linear cascade of airfoils externally oscillated in torsion and viewed tangentially at the shock surface. Three biconvex airfoils were subjected to harmonic pitching motion about the midchord axis at a frequency of 0.53 while immersed in a Mach 0.81 flow. Failure to produce observable shocks led to use of choked flow with a Mach number near one, of which 50 holograms were taken. The images revealed a narrow shock surface with a spanwise variation in the shock properties. The method is concluded to be useful for examining transonic flowfield shocks in the presence of airfoil flutter.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Aug. 198
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  • 60
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    Numerical solutions for the spin-up of a stratified fluid (1982)
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    Publication Date: 2011-08-18
    Description: The model of Warn-Varnas et al. (1978) is used to numerically examine the spin-up flow of a thermally stratified fluid in a cylinder with an insulating side wall, and comparison of the results with the laser-Doppler measurements of Lee (1975) shows excellent agreement. It is shown that flow gradients are created in the interior of the fluid during the meridional circulation spin-up phase, and that the azimuthal flow decayed faster than has been predicted by Wallin (1969). It is established that viscous diffusion in the interior, arising from the interior-flow gradients, is the cause of the discrepancy with Wallin's theory.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 117; Apr. 198
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  • 61
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    Unsteady airfoils (1982)
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    Publication Date: 2011-08-18
    Description: Progress towards successful modelling of unsteady flows past two-dimensional oscillating airfoils is examined. Linearized, thin airfoil theory is reviewed with special regard to the vortex shedding which occurs when either the body or the flow fluctuates. A sinusoidally oscillating flat-plate airfoil is considered in terms of noncirculatory components, including boundary conditions and bound and wake vortices, respectively. Applications of linear theory to vertical airfoil oscillations and to oscillating control surfaces are described, and oscillating airfoils in subsonic and supersonic flows are investigated. Perturbations in linear solutions are explored for the occurrence of second-order effects, and trailing edge and wake effects. The effects of unsteady transonic flows are broken into nearly inviscid and strongly viscous cases, and analyses of dynamic stall and stall flutter are presented.
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    Topology of three-dimensional separated flows (1982)
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    Publication Date: 2011-08-18
    Description: A Legendre formulation for a pattern of streamlines adjacent to a surface considered as trajectories with properties consistent with those of a constant vector field is used to develop a mathematical framework for three-dimensional separated flows. Convergence of skin-friction lines onto a particular skin-friction line originating from a particular saddle point is defined as a necessary condition for flow separation. Steady, three-dimensional flow is considered, and singular points occurring in the skin-friction lines are shown to happen where the skin friction or the surface vorticity become zero, and become nodal or saddle points. The separation initiates and continues only globally, as a mixture of an infinite set of friction lines, or locally, with one line. The topography of streamlines in two-dimensional sections of three-dimensional flows is discussed, and examples are provided of a round-nosed body of revolution at varying angles of attack.
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    Effect of thickness on airfoil surface noise (1982)
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    Publication Date: 2011-08-18
    Description: Noise emission from very small chord and very large chord airfoils was measured with eleven 0.63 cm microphones placed along a horizontal semicircle (4.57 m radius) that was centered at the leading edge of the test airfoil. The noise signals were analyzed by an automated spectrum analyzer which yielded 1/3-octave band sound pressure level spectra for each microphone, and the data were corrected to remove the effects of atmospheric attenuation and jet noise. It is found that the effect of thickness is large and must be accounted for in any fundamental airfoil noise theory that attempts to describe the noise emitted from real airfoils. Incident mean velocity gradients and compressibility must also be taken into account. The effect of thickness increases with frequency, with thick airfoils being quieter than thin ones.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Mar. 198
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    Heat transfer from combustion gases to a single row of closely spaced tubes in a swirl crossflow Stirling engine heater (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper describes an experimental program to determine the heat-transfer characteristics of a combustor and heat-exchanger system in a hybrid solar receiver which utilizes a Stirling engine. The system consists of a swirl combustor with a crossflow heat exchanger composed of a single row of 48 closely spaced curved tubes. In the present study, heat-transfer characteristics of the combustor/heat-exchanger system without a Stirling engine have been studied over a range of operating conditions and output levels using water as the working fluid. Nondimensional heat-transfer coefficients based on total heat transfer have been obtained and are compared with available literature data. The results show significantly enhanced heat transfer for the present geometry and test conditions. Also, heat transfer along the length of the tubes is found to vary, the effect depending upon test condition.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    The dependence of the shape and stability of captive rotating drops on multiple parameters (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Asymptotic and numerical techniques in bifurcation theory are applied to the Young-Laplace equation governing meniscus shape in order to analyze the dependence of the shape and stability of rigidly rotating drops held captive between corotating solid faces on multiple parameters. Asymptotic analysis of the evolution of drop shape from the cylindrical as a function of distance between the solid faces, drop volume, rotational Bond number and gravitational Bond number shows that some shape bifurcations from cylinders to wavy, axisymmetric menisci are ruptured by small changes in drop volume or gravity. Computer calculations of axisymmetric drop shapes based on a finite element representation of the interface and numerical algorithms for tracking shape families and singular points are then used to map drop stability for the four-dimensional parameter space. The results of the asymptotic and numerical analyses are shown to agree well within the limited range of parameters where the asymptotic analysis is valid.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Philosophical Transactions, Series A (ISSN 0080-4614); 306; 1493,; Aug. 27
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    ADI on staggered mesh - A method for the calculation of compressible convection (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An alternating direction implicit (ADI) method has been applied to a staggered grid for the computation of convection in a highly stratified fluid. Since artificial viscosity is not needed, subtle effects like the onset of convection can be studied. These computations compare well with the 2-D results by Graham (1975) and also agree with standard Boussinesq results when taken to that limit. Good efficiency has been achieved with a time step hundreds of times larger than the stability limit imposed by the explicit treatment of diffusion and the Courant number is not restricted to be below 1. The Navier-Stokes equation contains cross spatial derivatives which are treated explicitly in most ADI schemes. The destabilizing effect of such a practice on a 2-D model system with second-order spatial derivative terms only was analyzed and found to be not excessive.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics (ISSN 0021-9991); 47; July 198
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    A high-resolution numerical technique for inviscid gas-dynamic problems with weak solutions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The shock resolution of Harten's (1982) second-order explicit method for one-dimensional hyperbolic conservation laws is investigated for a two-dimensional gas-dynamic problem. The possible extension to a high resolution implicit method for both one- and two-dimensional problems is also investigated. Applications of Harten's method to the quasi-one-dimensional nozzle problem with two nozzle shapes (divergent and convergent-divergent) and the two-dimensional shock-reflection problem resulted in high shock resolution steady-state numerical solutions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Numerical solution of viscous flow in unbounded fluid (1982)
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    Publication Date: 2011-08-18
    Description: Incompressible viscous flow fields induced by initial vorticity distributions with bounded support or exponential decay in the far field are investigated. A numerical scheme for the solution of the vorticity distribution and the velocity field is presented with special emphasis on the treatment of the boundary data. The efficiency of the scheme is demonstrated. The present method has been applied to the study of the merging and collision of vortex rings.
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    Simulation of large turbulent vortex structures with the parabolic Navier-Stokes equations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The theoretical basis for well posed marching of a Parabolic Navier-Stokes (PNS) computational technique for supersonic flow is discussed and examples given to verify the analysis. It is demonstrated that stable computations can be made even with very small steps in the marching direction. The method is applied to cones at large angle of attack in high Reynolds number, supersonic flow. Streamline trajectories generated from the numerical solutions demonstrate the development of vortex structures of the lee side of the cone. Previously announced in STAR as N83-22551
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Relaxation solution of the full Euler equations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A numerical procedure for the relaxation solution of the full steady Euler equations is described. By embedding the Euler system in a second order surrogate system, central differencing may be used in subsonic regions while retaining matrix forms well suited to iterative solution procedures and convergence acceleration techniques. Hence, this method allows the development of stable, fully conservative differencing schemes for the solution of quite general inviscid flow problems. Results are presented for both subcritical and shocked supercritical internal flows. Comparisons are made with a standard time dependent solution algorithm. Previously announced in STAR as N82-24859
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    Pointwise and scanning laser anemometer measurements in steady and unsteady separated turbulent boundary layers (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The physical features of steady and unsteady freestream separating turbulent boundary layers that have been determined by pointwise laser anemometer measurements are outlined. It is seen that the large-scale structures control the outer region's backflow behavior. Near the wall, the mean backflow velocity profile for both the steady and unsteady cases is found to scale on the maximum negative mean velocity and its distance from the wall. A description is given of a scanning laser anemometer that produces nearly instantaneous velocity profiles for examing the temporal features of these large-scale structures. Also described is a 'zero-wake' seeder that supplies particles to the outer shear layer and freestream flow with a minimal disturbance.
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    A new numerical method for the simulation of three-dimensional flow in a pipe (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new numerical technique for simulating three dimensional, unsteady, incompressible pipe flows is presented and its utility and accuracy is shown. Each vector function in the expansion of the velocity field is divergence free and satisfies the boundary conditions for viscous flow. Some of the benefits of the expansion technique are that pressure is eliminated from the dynamics, only two unknowns per mesh point are required, implicit treatment of the viscous terms is provided at no extra computational cost, and no fractional time steps are required. The method uses spectral expansions: Fourier series in the azimuthal and streamwise directions, and Jacobi polynominals in the radial direction. Previously announced in STAR as N82-31644
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Numerical simulation of wall-bounded turbulent shear flows (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Developments in three dimensional, time dependent numerical simulation of turbulent flows bounded by a wall are reviewed. Both direct and large eddy simulation techniques are considered within the same computational framework. The computational spatial grid requirements as dictated by the known structure of turbulent boundary layers are presented. The numerical methods currently in use are reviewed and some of the features of these algorithms, including spatial differencing and accuracy, time advancement, and data management are discussed. A selection of the results of the recent calculations of turbulent channel flow, including the effects of system rotation and transpiration on the flow are included. Previously announced in STAR as N82-28577
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Analysis of separated boundary-layer flows (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A method for predicting the strong interaction between the viscous and inviscid flows which occurs in flow separation is reviewed. An inverse boundary-layer procedure approximately accounts for normal pressure gradients that may be important in strongly interacting flows. Transformed boundary-layer equations are written in which the pressure gradient is set equal to the inviscid pressure gradient. As the boundary-layer edge is approached and the viscous shear and heat conduction terms vanish, the viscous flow solution is required to asymptotically approach the inviscid solution over the generalized displacement body. Attention is then focused on viscous-inviscid interacting flows with a first-order viscous formulation and constant pressure across the boundary layer. Results obtained with this procedure are presented for: (1) transitional separation bubbles near an airfoil leading edge, (2) subsonic boattail separated turbulent flow, and (3) transonic turbulent shock wave boundary-layer interaction on an axisymmetric bump configuration.
    Keywords: AERODYNAMICS
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    Computational aerodynamics and design (1982)
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    Publication Date: 2011-08-18
    Description: The role of computational aerodynamics in design is reviewed with attention given to the design process; the proper role of computations; the importance of calibration, interpretation, and verification; the usefulness of a given computational capability; and the marketing of new codes. Examples of computational aerodynamics in design are given with particular emphasis on the Highly Maneuverable Aircraft Technology. Finally, future prospects are noted, with consideration given to the role of advanced computers, advances in numerical solution techniques, turbulence models, complex geometries, and computational design procedures. Previously announced in STAR as N82-33348
    Keywords: AERODYNAMICS
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    Three-dimensional separation and reattachment (1982)
    In:  CASI
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    Publication Date: 2017-10-02
    Description: The separation of three dimensional turbulent boundary layers from the lee of flight vehicles at high angles of attack is investigated. The separation results in dominant, large scale, coiled vortex motions that pass along the body in the general direction of the free stream. In all cases of three dimensional flow separation and reattachment, the assumption of continuous vector fields of skin friction lines and external flow streamlines, coupled with simple laws of topology, provides a flow grammar whose elemental constituents are the singular points: the nodes, spiral nodes (foci), and saddles. The phenomenon of three dimensional separation may be constrained as either a local or a global event, depending on whether the skin friction line that becomes a line of separation originates at a node or a saddle point.
    Keywords: AERODYNAMICS
    Type: AGARD High Angle-of-Attack Aerodyn.; 14 p
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    Three-dimensional flows about simple components at angle of attack (1982)
    In:  CASI
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    Publication Date: 2017-10-02
    Description: The structures of three dimensional separated flow about some chosen aerodynamic components at angle of attack are synthesized, holding strictly to the notion that streamlines in the external flow (viscous plus inviscid) and skin friction lines on the body surface may be considered as trajectories having properties consistent with those of continuous vector fields. Singular points in the fields are of limited number and are classified as simple nodes and saddles. Analogous flow structures at high angles of attack about blunt and pointed bodies, straight and swept wings, etc., are discussed, highlighting the formation of spiral nodes (foci) in the pattern of the skin friction lines. How local and global three dimensional separation lines originate and form is addressed, and the characteristics of both symmetric and asymmetric leeward wakes are described.
    Keywords: AERODYNAMICS
    Type: AGARD High Angle-of-Attack Aerodyn.; 56 p
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    Control of the forebody vortex orientation by asymmetric air injection. Part A: Application to enhance departure/spin recovery of fighter aircraft. Part B: Details of the flow structure (1982)
    In:  CASI
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    Publication Date: 2017-10-02
    Description: A novel concept which was developed to provide powerful directional control effectiveness for a fighter aircraft at high angles of attack, where more traditional controls have very limited capability is discussed. The concept utilizes the energy concentrated in the strong forebody vortices (which form on slender bodies at high relative incidence) by controlling the lateral orientation of the vortices with respect to the body. The present concept seeks to utilize the inherent sensitivity of the vortex positioning and its bistable nature to an advantage allowing control of the forces which are developed. As it turns out, the direction or sense of the asymmetric vortex pair is much easier to control than to attenuate. The work which was done to develop the concept for application to an aircraft is described and is directed toward the effects of the concept on aircraft forces and moments and on the flight mechanics of the aircraft during maneuvering at high angles of attack. The objective was to utilize the side force associated with asymmetric vortices, in a controlled manner, to enhance the ability of the fighter to recover from a departure from controlled flight. The results from these water tunnel and wind tunnel experiments show that a small amount of tangential blowing along the forebody near the apex can effectively alter the forebody vortex system and generate large restoring yawing moments.
    Keywords: AERODYNAMICS
    Type: AGARD High Angle-of-Attack Aerodyn.; 22 p
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    Jet V/STOL wind-tunnel simulation and groundplane effects (1982)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: The pretest preparation necessary to define the objectives of an appropriate investigation into the jet V/STOL wind tunnel simulation and ground plane effects were examined. Low speed wind tunnel testing of V/STOL aircraft concepts to determine the aerodynamic propulsion interaction effects during the transition between hover and wingborne flight is a necessary step in the development cycle of this type of aircraft. Powered models are normally used to determine the aerodynamic performance characteristics. Several factors which influence the selection of the model concept and the engine simulator are discussed. Some of the test techniques important for this class of aircraft model are examined. Wind tunnel wall effects important to this aircraft testing with special emphasis on groundplane effects are reviewed.
    Keywords: AERODYNAMICS
    Type: AGARD Fluid Dyn. of Jets with Appl. to V(STOL; 21 p
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    An evaluation of superminicomputers for thermal analysis (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The use of superminicomputers for solving a series of increasingly complex thermal analysis problems is investigated. The approach involved (1) installation and verification of the SPAR thermal analyzer software on superminicomputers at Langley Research Center and Goddard Space Flight Center, (2) solution of six increasingly complex thermal problems on this equipment, and (3) comparison of solution (accuracy, CPU time, turnaround time, and cost) with solutions on large mainframe computers.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Computational Aspects of Heat Transfer in Struct.; p 437-451
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    Effects of rotation and magnetic field on the onset of convective instability in a liquid layer due to buoyancy and surface tension (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Thermocapillary stability characteristics of a horizontal liquid layer heated from below rotating about a vertical axis and subjected to a uniform vertical magnetic field are analyzed under a variety of thermal and electromagnetic boundary conditions. Results based on analytical solutions to the pertinent eigenvalue problems are discussed in the light of earlier work on special cases of the more general problem considered here to show in particular the effects of the heat transfer, nonzero curvature and gravity waves at the two-fluid interface. Although the expected stabilizing action of the Coriolis and Lorentz force fields in this configuration are in evidence the optimal choice of an appropriate range for the relevant parameters is shown to be critically dependent on the interfacial effects mentioned above.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 366-373
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    The geophysical importance of bubbles in the sea (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Present knowledge of the mechanisms for production and enrichment and film drops by bursting bubbles is summarized, with particular emphasis on the unsolved problems. Sea salt is by far the major constituent cycled through the Earth's atmosphere each year. Bursting bubbles in the oceans appear to be primarily responsible. These salt particles play a role in the formation of maritime clouds, which in turn affect the Earth's radiation budget. Along with the salt are carried various chemical pollutants and potentially pathogenic microorganisms, often in highly enriched form.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 255-259
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    Raindrop oscillations (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A model of the change in shape of a raindrop is presented. Raindrops measured by two orthogonal cameras were classified by shape and orientation to determine the nature of the oscillation. A physical model based on potential energy was then developed to study the amplitude variation of oscillating drops. The model results show that oscillations occur about the equilibrium axis ratio, but the time average axis ratio if significantly more spherical for large amplitudes because of asymmetry in the surface potential energy. A generalization of the model to oscillations produced by turbulence yields average axis ratios that are consistent with the camera measurements. The model results for average axis ratios were applied to rainfall studies with a dual polarized radar.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 244-246
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    A wind tunnel investigation of the shape of uncharged raindrops in the presence of an external, electric field (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Results of a wind tunnel experiment in which electrically uncharged water drops of 500 to 3000 microns equivalent radius are freely suspended in the vertical air stream of the UCLA cloud tunnel are presented. During this suspension the drops were exposed to external vertical electric fields of 500 to 8,000 volts/cm. The change in drop shape with drop size and electric field strength was noted and is discussed in the light of theoretical work cited in the literature which unfortunately does not take into account the effects of air flow past the drop. The wind tunnel study is documented by stills from a 16 mm film record that demonstrates the shape of water drops in response to both hydrodynamic and electric forces.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 239-243
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    Bubble shapes in steady axisymmetric flows at intermediate Reynolds number (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The shape of a gas bubble which rises through a quiescent incompressible, Newtonian fluid at intermediate Reynolds numbers is considered. Exact numerical solutions for the velocity and pressure fields, as well as the bubble shape, are obtained using finite difference techniques and a numerically generated transformation to an orthogonal, boundary-fitted coordinate system. No restriction is placed on the allowable magnitude of deformation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 151-156
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    Holographic studies of the vapor explosion of vaporizing water-in-fuel emulsion droplets (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Holographic studies were performed which examined the fragmentation process during vapor explosion of a water-in-fuel (hexadecane/water) emulsion droplet. Holograms were taken at 700 to 1000 microseconds after the vapor explosion. Photographs of the reconstructed holograms reveal a wide range of fragment droplet sizes created during the explosion process. Fragment droplet diameters range from below 10 microns to over 100 microns. It is estimated that between ten thousand and a million fragment droplets can result from this extremely violent vapor explosion process. This enhanced atomization is thus expected to have a pronounced effect on vaporization processes which are present during combustion of emulsified fuels.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 112-119
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    Behavior of liquid hydrogen inside an ICF target (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The configuration of liquid hydrogen inside spherical glass shell ICF target was studied both theoretically and experimentally. Because of the zero contact angle between the .D2 liquid and glass substrate and the limited wetting surface that is continuous, the liquid hydrogen completely covers the interior of the glass shell, resulting in the formation of a void at the center. For this reason, the present problem distinguishes itself from that for a sessile drop sitting on a flat surface. A theory was formulated to calculate the liquid hydrogen configuration by including the London-dispersion force between the liquid and the substrate molecules. The net result is an augmented Bashforth-Adams equation appropriate to a spherical substrate, which is considered to be the major contribution of the present work. Preliminary calculations indicate that this equation accurately models the liquid hydrogen behavior inside a spherical microshell.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 96-106
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    NASTRAN thermal analyzer in a unified finite-element treatment of thermo-structural analyses (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The NASTRAN thermal analyzer (NTA) which performs large-scale unified thermo-structural analyses with the NASTRAN (NASA structural analysis) computer program is described. The mathematical similitude between these two distinct disciplines of thermal and structure is examined. It serves as the theoretical basis upon which the implementation of the thermal capability in NASTRAN was accomplished. The program structure, the functional flow, the solution algorithms, the organization of an input data deck and the solution capabilities of NTA are summarized. Emphasis is placed on the interface of the unified approach in thermo-structural analyses where stresses, deflections, vibrations and bucklings induced by the effect of temperature change are of concern. Attentions are also directed to the preprocessor and post processors. As a specially designed preprocessor, the VIEW program is capable of generating exchange factors which can be output, at user's option, in formats compatible with that required by NTA. Two post processors that serve specific objectives are included. They are the thermal variance analysis and the graphical displaying capability of temperatures in color or black and white.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center Computational Aspects of Heat Transfer in Struct.; p 1-22
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    Profiles of electrified drops and bubbles (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Axisymmetric equilibrium shapes of conducting drops and bubbles, (1) pendant or sessile on one face of a circular parallel-plate capacitor or (2) free and surface-charged, are found by solving simultaneously the free boundary problem consisting of the augmented Young-Laplace equation for surface shape and the Laplace equation for electrostatic field, given the surface potential. The problem is nonlinear and the method is a finite element algorithm employing Newton iteration, a modified frontal solver, and triangular as well as quadrilateral tessellations of the domain exterior to the drop in order to facilitate refined analysis of sharply curved drop tips seen in experiments. The stability limit predicted by this computer-aided theoretical analysis agrees well with experiments.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 322-329
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    Asymptotic Expansions and Estimates for the Capillary Problem (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The asymptotic properties for the small Bond number B of the equilibrium capillary interface interior to a circular cylindrical tube vertically dipped in an infinite reservoir of liquid are discussed. (The Bond number B is a dimensionless parameter which is the ratio of gravitational to capillary forces.) The formal expansion in powers of B of the solution to the differential equation describing the equilibrium surface (as can be obtained by standard perturbation methods) is proved to be truly asymptotic -- to all orders and uniformly in the variable and parameter gamma, the contact angle. Sequences of general estimates, in closed form, from above and from below, are also given for the solution and related functions. The M-th term in these sequences are asymptotically exact to order m. An idiosyncrasy of the problem, crucial in obtaining these estimates, is the absolute monotonicity of the structural function of the system in integral form.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 344-349
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    Fluid dynamical description of relativistic nuclear collisions (1982)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: On the basis of both a conventional relativistic nuclear fluid dynamic model and a two fluid generalization that takes into account the interpenetration of the target and projectile upon contact, collisions between heavy nuclei moving at relativistic speeds are calculated. This is done by solving the relevant equations of motion numerically in three spatial dimensions by use of particle in cell finite difference computing techniques. The effect of incorporating a density isomer, or quasistable state, in the nuclear equation of state at three times normal nuclear density, and the effect of doubling the nuclear compressibility coefficient are studied. For the reaction 20Ne + 238U at a laboratory bombarding energy per nucleon of 393 MeV, the calculated distributions in energy and angle of outgoing charged particles are compared with recent experimental data both integrated over all impact parameters and for nearly central collisions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 260-267
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  • 92
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    Capillary surface discontinuities above reentrant corners (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A particular configuration of a vertical capillary tube for which S is the equilibrium interface between two fluids in the presence of a downward pointing gravitational field was investigated. S is the graph a function u whose domain is the (horizontal) cross section gamma of the tube. The mean curvature of S is proportional to its height above a fixed reference plane and lambda is a prescribed constant and may be taken between zero and pi/2. Domains gamma for which us is a bounded function but does not extend continuously to d gamma are sought. Simple domains are found and the behavior of u in those domains is studied. An important comparison principle that has been used in the literature to derive many of the results in capillarity is reviewed. It allows one to deduce the approximate shape of a capillary surface by constructing comparison surfaces with mean curvature and contact angle close to those of the (unknown) solution surface. In the context of nonparametric problems the comparison principle leads to height estimates above and below for the function u. An example from the literature where these height estimates have been used successfully is described. The promised domains for which the bounded u does not extend continuously to the boundary are constructed. The point on the boundary at which u has a jump discontinuity will be the vertext of a re-entrant corner having any interior angle theta pi. Using the comparison principle the behavior of u near this point is studied.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 295-302
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  • 93
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    Drop rebound in clouds and precipitation (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The possibility of rebound for colliding cloud drops was measured by determining the collection efficiency. The collection efficiency for 17 size pairs of relatively uncharged drops in over 500 experimental runs was measured using two techniques. The collection efficiencies fall in a narrow range of 0.60 to 0.70 even though the collection drop was varied between 63 and 326 microns and the size ratio from 0.05 to 0.33. In addition the measured values of collection efficiencies (Epsilon) were below the computed values of collision efficiencies (E) for rigid spheres. Therefore it was concluded that rebound was occurring for these sizes since inferred coalescence (epsilon = Epsilon/E) efficiencies are about 0.6 yo 0.8. At a very small size ratio (r/R = p = 0.05, R = 326 microns) the coalescence efficiency inferred is in good agreement with the experimental findings for a supported collector drop. At somewhat large size ratios the inferred values of epsilon are well above results of supported drop experiments, but show a slight correspondence in collected drop size dependency to two models of drop rebound. At a large size ratio (p = 0.73, R = 275) the inferred coalescence efficiency is significantly different from all previous results.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 247-254
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  • 94
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    Resonances, radiation pressure and optical scattering phenomena of drops and bubbles (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Acoustic levitation and the response of fluid spheres to spherical harmonic projections of the radiation pressure are described. Simplified discussions of the projections are given. A relationship between the tangential radiation stress and the Konstantinov effect is introduced and fundamental streaming patterns for drops are predicted. Experiments on the forced shape oscillation of drops are described and photographs of drop fission are displayed. Photographs of critical angle and glory scattering by bubbles and rainbow scattering by drops are displayed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 166-174
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  • 95
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    Droplets Generated from a new OGEE shaped, liquid, air-shear, electrostatic nozzle (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A series of experimental tests was carried out on an 'OGEE' shaped planform, liquid air-shear electrostatic nozzle. Liquid was ejected from the upper surface of the nozzle and was then dispersed and atomized efficiently by a high speed air flow passing over the nozzle and by the effect of two very strong coherent air vortices generated by the 'OGEE' shaped nozzle surface. Initial test results which are presented show the nozzle to perform far superior to a similar delta wing shaped design which is used extensively in various industries applications.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 120-123
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  • 96
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    An experimental investigation of circulation control flow fields using holographic interferometry (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Experiments are presented which were conducted on flow fields produced by a circulation control airfoil utilizing the Coanda effect at the trailing edge. The application of holographic interferometry to obtain both visualization and quantitative data on the flow field about a circulation control airfoil at transonic flow speed is covered. A brief description of the flow model and measurement techniques is given. The data reduction procedure, results, and interpretation are presented. The results have provided a good deal of information on the character of the flow field, particularly in the neighborhood of the trailing edge. As to the airfoil design, it is apparent that improved performance can be achieved if jet detachment is delayed. Another design improvement would involve the development of an optimum trailing-edge shape for the expected operating Mach and Reynolds number ranges.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-CR-166482 , NAS 1.26:166482
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  • 97
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    Thermal radiation view factor: Methods, accuracy and computer-aided procedures (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The computer aided thermal analysis programs which predicts the result of predetermined acceptable temperature range prior to stationing of these orbiting equipment in various attitudes with respect to the Sun and the Earth was examined. Complexity of the surface geometries suggests the use of numerical schemes for the determination of these viewfactors. Basic definitions and standard methods which form the basis for various digital computer methods and various numerical methods are presented. The physical model and the mathematical methods on which a number of available programs are built are summarized. The strength and the weaknesses of the methods employed, the accuracy of the calculations and the time required for computations are evaluated. The situations where accuracies are important for energy calculations are identified and methods to save computational times are proposed. Guide to best use of the available programs at several centers and the future choices for efficient use of digital computers are included in the recommendations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Marshall Space Flight Center The 1982 NASA(ASEE Summer Fac. Fellowship Program; 58 p
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  • 98
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    Some aspects of algorithm performance and modeling in transient thermal analysis of structures (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The status of an effort to increase the efficiency of calculating transient temperature fields in complex aerospace vehicle structures is described. The advantages and disadvantages of explicit and implicit algorithms are discussed. A promising set of implicit algorithms with variable time steps, known as the GEAR package is described. Four test problems, used for evaluating and comparing various algorithms, were selected and finite element models of the configurations are described. These problems include a space shuttle frame component, an insulated cylinder, a metallic panel for a thermal protection system, and a model of the space shuttle orbiter wing. Results generally indicate a preference for implicit oer explicit algorithms for solution of transient structural heat transfer problems when the governing equations are stiff.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Computational Aspects of Heat Transfer in Struct.; p 91-98
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  • 99
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    A method to model latent heat for transient analysis using NASTRAN (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A sample heat transfer analysis is demonstrated which includes the heat of fusion. The method can be used to analyze a system with nonconstant specific heat. The enthalpy is introduced as an independent degree of freedom at each node. The user input consists of a curve of temperature as a function of enthalpy, which may include a constant temperature phase change. The basic NASTRAN heat transfer capability is used to model the effects of latent heat with existing direct matrix output and nonlinear load data cards. Although some user care is required, the numerical stability of the integration is quite good when the given recommendations are followed. The theoretical equations used and the NASTRAN techniques are shown.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center Computational Aspects of Heat Transfer in Struct.; p 83-89
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  • 100
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    Studies of the nucler equation of state using numerical calculations of nuclear drop collisions (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A numerical calculation for the full thermal dynamics of colliding nuclei was developed. Preliminary results are reported for the thermal fluid dynamics in such processes as Coulomb scattering, fusion, fusion-fission, bulk oscillations, compression with heating, and collisions of heated nuclei.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: JPL Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 268-279
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