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  • AERODYNAMICS  (420)
  • 1980-1984  (419)
  • 1940-1944
  • 1925-1929  (1)
  • 1982  (419)
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  • 101
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    Computer program for calculating full potential transonic, quasi-three-dimensional flow through a rotating turbomachinery blade row (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A fast, reliable computer code is described for calculating the flow field about a cascade of arbitrary two dimensional airfoils. The method approximates the three dimensional flow in a turbomachinery blade row by correcting for stream tube convergence and radius change in the throughflow direction. A fully conservative solution of the full potential equation is combined with the finite volume technique on a body-fitted periodic mesh, with an artificial density imposed in the transonic region to insure stability and the capture of shock waves. The instructions required to set up and use the code are included. The name of the code is QSONIC. A numerical example is also given to illustrate the output of the program.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2030 , E-1013 , NAS 1.60:2030
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  • 102
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    Calculation of three-dimensional, inviscid supersonic, steady flows (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A numerical technique is described for the calculation of three dimensional, inviscid, supersonic, steady flows over wing-body configurations. A high degree of accuracy without increasing the number of computational nodes is obtained by means of a powerful conformal mapping technique. Results are presented for some simple body configurations and for a more complex arrow wing airframe. The numerical results show good agreement with experimental measurements.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3573 , NAS 1.26:3573
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  • 103
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    AGARD three-dimensional aeroelastic configurations (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The calculation of unsteady aerodynamic forces in the critical transonic speed regime is investigated. The development of such methods is be enhanced by the availability of a limited number of test cases for the comparison of competing methods. Test cases for five clean, isolated wings are presented. Wing geometric descriptions, airfoil coordinates, and suggested aerodynamic conditions for each are included.
    Keywords: AERODYNAMICS
    Type: NASA-TM-84708 , NAS 1.15:84708 , AGARD-AR-167 , AD-A115045
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  • 104
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    Three-dimensional flows about simple components at angle of attack (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    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: NASA-TM-84226 , A-8859 , NAS 1.15:84226 , PAPER-2
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  • 105
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    GRID3C: Computer program for generation of C type multilevel, three dimensional and boundary conforming periodic grids (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A fast computer program, GRID3C, was developed for accurately generating periodic, boundary conforming, three dimensional, consecutively refined computational grids applicable to realistic axial turbomachinery geometries. The method is based on using two functions to generate two dimensional grids on a number of coaxial axisymmetric surfaces positioned between the centerbody and the outer radial boundary. These boundary fitted grids are of the C type and are characterized by quasi-orthogonality and geometric periodicity. The built in nonorthogonal coordinate stretchings and shearings cause the grid clustering in the regions of interest. The stretching parameters are part of the input to GRID3C. In its present version GRID3C can generate and store a maximum of four consecutively refined three dimensional grids. The output grid coordinates can be calculated either in the Cartesian or in the cylindrical coordinate system.
    Keywords: AERODYNAMICS
    Type: NASA-CR-167846 , NAS 1.26:167846
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  • 106
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    Steady, Oscillatory, and Unsteady Subsonic and Supersonic Aerodynamics, production version 1.1 (SOUSSA-P1.1). Volume 2: User/programmer manual. Addendum 1: Analytical treatment of wake influence (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The influence of the trailing wake at each wing panel center is investigated. The effect of the wake is calculated by analyzing the wake as being subdivided into trailing wake strips. With the improved program there are two optional ways of calculating the wake effect, and the choice is controlled by an added parameter KANW that is part of the input data.
    Keywords: AERODYNAMICS
    Type: NASA-TM-84484 , NAS 1.15:84484
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  • 107
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    Static internal performance characteristics of two thrust reverser concepts for axisymmetric nozzles (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The statis performance of two axisymmetric nozzle thrust reverser concepts was investigated. A rotating vane thrust reverser represented a concept in which reversing is accomplished upstream of the nozzle throat, and a three door reverser concept provided reversing downstream of the nozzle throat. Nozzle pressure ratio was varied from 2.0 to approximately 6.0. The results of this investigation indicate that both the rotating vane and three door reverser concepts were effective static thrust spoilers with the landing approach nozzle geometry and were capable of providing at least a 50 percent reversal of static thrust when fully deployed with the ground roll nozzle geometry.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2025 , NAS 1.60:2025
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  • 108
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    Performance characteristics of axisymmetric convergent-divergent exhaust nozzles with longitudinal slots in the divergent (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An investigation was conducted in the Langley 16 foot Transonic Tunnel and in the static test facility of that tunnel to determine the effects of divergent flap ventilation of an axisymmetric nozzle on nozzle internal (static) and wind on performance. Tests were conducted at 0 deg angle of attack at static conditions and at Mach numbers from 0.6 to 1.2. Ratios of jet total pressure to free stream static pressure were varied from 1.0 (jet off) to approximately 14.0 depending on Mach number. The results of this study indicate that divergent flap ventilation generally provided large performance benefits at overexpanded nozzle conditions and performance reductions at underexpanded nozzle conditions when compared to the baseline (unventilated) nozzles. Ventilation also reduced the peak static and wind on performance levels.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2013 , L-15119 , NAS 1.60:2013
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  • 109
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    Performance of a 2D-CD nonaxisymmetric exhaust nozzle on a turbojet engine at altitude (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Baseline thrust and cooling data obtained with a 2D-CD versatile research exhaust nozzle mounted on a turbojet engine in an altitude chamber are presented. The tests covered a range of nozzle pressure ratios, nozzle pressure ratios, nozzle throat areas, and internal expansion area ratios. The thrust data obtained show good agreement with theory and scale model results after correcting the data for leakage and bypass cooling flows. Additional work is needed to improve predictability of cooling performance.
    Keywords: AERODYNAMICS
    Type: NASA-TM-82881 , E-1257 , NAS 1.15:82881
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  • 110
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    Free Wake Techniques for Rotor Aerodynamic Analylis. Volume 2: Vortex Sheet Models (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Results of computations are presented using vortex sheets to model the wake and test the sensitivity of the solutions to various assumptions used in the development of the models. The complete codings are included.
    Keywords: AERODYNAMICS
    Type: NASA-CR-166435 , NAS 1.26:166435 , ASRL-TR-199-2
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  • 111
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    Three dimensional flow computations in a turbine scroll (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The compressible three dimensional inviscid flow in the scroll and vaneless nozzle of radial inflow turbines is analyzed. A FORTRAN computer program for the numerical solution of this complex flow field using the finite element method is presented. The program input consists of the mass flow rate and stagnation conditions at the scroll inlet and of the finite element discretization parameters and nodal coordinates. The output includes the pressure, Mach number and velocity magnitude and direction at all the nodal points.
    Keywords: AERODYNAMICS
    Type: NASA-CR-168003 , NAS 1.26:168003
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  • 112
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    Calculation of compressible flow in and about three-dimensional inlets with and without auxiliary inlets by a higher-order panel method (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A three dimensional higher order panel method was specialized to the case of inlets with auxiliary inlets. The resulting program has a number of graphical input-output features to make it highly useful to the designer. The various aspects of the program are described instructions for its use are presented.
    Keywords: AERODYNAMICS
    Type: NASA-CR-168009 , NAS 1.26:168009 , MDC-J2548
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  • 113
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    Solution of the unsteady subsonic thin airfoil problem (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The problem of a thin airfoil subject to simple harmonic disturbances in a uniform subsonic free stream is solved by extension of a technique developed earlier for a stationary strip vibrating in a uniform fluid. Explicit expressions are given for the lift and moment, acoustic directivity pattern, and total acoustic power for arbitrary upwash and, in particular, for the 'elementary disturbances': plunge, pitch and a stationary transverse gust. Numerical results for a simple skewed gust are presented and compared to the high-frequency asymptotic theory of Martinez and Widnall.
    Keywords: AERODYNAMICS
    Type: Quarterly Journal of Mechanics and Applied Mathematics; 35; Aug. 198
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  • 114
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    Stagnation point heat transfer augmentation due to free stream turbulence (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A model has been proposed for the momentum eddy diffusivity induced by free stream turbulence intensity and integral length scale. The eddy diffusivity model is applied to the stagnation point of a cylinder situated in a uniform crossflow in the presence of free stream turbulence. A numerical solution of the governing momentum and energy equations with the proposed eddy diffusivity model yielded results for the skin friction coefficient and the Nusselt number. The numerical predictions of the present work are compared with experimental data and the agreement between the two is seen to be very good.
    Keywords: AERODYNAMICS
    Type: Applied Scientific Research; 39; 2, 19; 1982
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  • 115
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    Measurement and prediction of mean velocity and turbulence structure in the near wake of an airfoil (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: An experimental investigation of the near wake of a thin airfoil at various incidence angles is reported in this paper. The airfoil (NACA 0012 basic thickness form) was located in a wind tunnel, and the wake structure was measured using hot-wire sensors. The measurements of mean-velocity, turbulence intensity and Reynolds-stress components across the wake at several distances downstream show the complex nature of the near wake and its asymmetrical behavior. The asymmetry in the wake property, which is maintained up to a length of 1.5 chords downstream of the trailing edge of the blade, is dependent on the incidence angle of the inlet flow. The streamwise velocity defect in an asymmetric wake decays more slowly compared to that of a symmetric wake. The streamline curvature due to the blade loading has a substantial effect on the mean velocity profile as well as the turbulence structure. The numerical study of the same wake indicates that the existing turbulence closure models need some modification to account for the asymmetric characteristics of the wake.
    Keywords: AERODYNAMICS
    Type: Journal of Fluid Mechanics; 115; Feb. 198
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  • 116
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    A new solution method for lifting surfaces in subsonic flow (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A simple method for calculating the unsteady aerodynamic loadings on harmonically oscillating thin wings in subsonic flow has been developed. The method is based on a concept of concentrated lift forces. The wing is divided into the element surfaces on which lift distributions are represented by single concentrated lift forces. Since the procedure does not include any quadratures, it can be applied easily to calculate the unsteady aerodynamic loadings on complex planform wings even when they have partial span control surfaces. Numerical calculations are carried out for various wing geometries and compared with other analyses and experiments.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Mar. 198
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  • 117
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    Design of supercritical swept wings (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Computational fluid dynamics are used to discuss problems inherent to transonic three-dimensional flow past supercritical swept wings. The formulation for a boundary value problem for the flow past the wing is provided, including consideration of weak shock waves and the use of parabolic coordinates. A swept wing code is developed which requires a mesh of 152 x 10 x 12 points and 200 time cycles. A formula for wave drag is calculated, based on the idea that the conservation form of the momentum equation becomes an entropy inequality measuring the drag, expressible in terms of a small-disturbance equation for a potential function in two dimensions. The entropy inequality has been incorporated in a two-dimensional code for the analysis of transonic flow over airfoils. A method of artificial viscosity is explored for optimum pressure distributions with design, and involves a free boundary problem considering speed over only a portion of the wing.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Mar. 198
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  • 118
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    Laser anemometer measurements in an annular cascade of core turbine vanes and comparison with theory (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Laser measurements were made in an annular cascade of stator vanes operating at an exit critical velocity ratio of 0.78. Velocity and flow angles in the blade to blade plane were obtained at every 10 percent of axial chord within the passage and at 1/2 axial chord downstream of the vanes for radial positions near the hub, mean and tip. Results are presented in both plot and tabulated form and are compared with calculations from an inviscid, quasi three dimensional computer program. The experimental measurements generally agreed well with these theoretical calculations, an indication of the usefulness of this analytic approach.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2018 , E-876 , NAS 1.60:2018
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  • 119
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    The design and instrumentation of the Purdue annular cascade facility with initial data acquisition and analysis (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Three dimensional aerodynamic data, required to validate and/or indicate necessary refinements to inviscid and viscous analyses of the flow through turbomachine blade rows, are discussed. Instrumentation and capabilities for pressure measurement, probe insertion and traversing, and flow visualization are reviewed. Advanced measurement techniques including Laser Doppler Anemometers, are considered. Data processing is reviewed. Predictions were correlated with the experimental data. A flow visualization technique using helium filled soap bubbles was demonstrated.
    Keywords: AERODYNAMICS
    Type: NASA-CR-167861 , NAS 1.26:167861 , ME-TSPC-TR-82-11
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  • 120
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    An experimental investigation of gapwise periodicity and unsteady aerodynamic response in an oscillating cascade. 1: Experimental and theoretical results (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Tests were conducted on a linear cascade of airfoils oscillating in pitch to measure the unsteady pressure response on selected blades along the leading edge plane of the cascade, over the chord of the center blade, and on the sidewall in the plane of the leading edge. The pressure data were reduced to Fourier coefficient form for direct comparison, and were also processed to yield integrated loads and, particularly, the aerodynamic damping coefficient. Results from the unsteady Verdon/Caspar theory for cascaded blades with nonzero thickness and camber were compared with the experimental measurements. The three primary results are: (1) from the leading edge plane blade data, the cascade was judged to be periodic in unsteady flow over the range of parameters tested; (2) the interblade phase angle was found to be the single most important parameter affecting the stability of the oscillating cascade blades; and (3) the real blade theory and the experiment were in excellent agreement for the several cases chosen for comparison.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3513 , NAS 1.26:3513 , R81-914618-27
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  • 121
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    Aerodynamic performance of high turning core turbine vanes in a two dimensional cascade (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Experimental and theoretical aerodynamic performance data are presented for four uncooled high turning core turbine vanes with exit angles of 74.9, 75.0, 77.5, and 79.6 degrees in a two dimensional cascade. Data for a more conservative 67.0 degree vane are included for comparison. Correction of the experimental aftermix kinetic energy losses to a common 0.100 centimeter trailing edge thickness yields a linear trend of increased loss from 0.020 to 0.025 as the vane exit angle increases from 67.0 to 79.6 degrees. The theoretical losses show a similar trend. The experimental and theoretical vane surface velocity distributions generally agree within approximately five percent, although the suction surface theoretical velocities are generally higher than the experimental velocities as the vane exit angle increases.
    Keywords: AERODYNAMICS
    Type: NASA-TM-82894 , E-1272 , NAS 1.15:82894
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  • 122
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    Development of low-frequency kernel-function aerodynamics for comparison with time-dependent finite-difference methods (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Finite difference methods for unsteady transonic flow frequency use simplified equations in which certain of the time dependent terms are omitted from the governing equations. Kernel functions are derived for two dimensional subsonic flow, and provide accurate solutions of the linearized potential equation with the same time dependent terms omitted. These solutions make possible a direct evaluation of the finite difference codes for the linear problem. Calculations with two of these low frequency kernel functions verify the accuracy of the LTRAN2 and HYTRAN2 finite difference codes. Comparisons of the low frequency kernel function results with the Possio kernel function solution of the complete linear equations indicate the adequacy of the HYTRAN approximation for frequencies in the range of interest for flutter calculations.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83283 , L-15226 , NAS 1.15:83283
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  • 123
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    The modeling and prediction of multiple jet VTOL aircraft flow fields in ground effect (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An engineering methodology based on an empirical data base and analytical fluid dynamic models was developed for the prediction of propulsive lift system induced aerodynamic effects for multiple lift jet VTOL aircraft operating in the hover mode in and out of ground effect. The effects of aircraft geometry, aircraft orientation (pitch, roll) as well as height above ground are considered. Lift jet vector and splay directions fit the airframe, lift jet exit flow conditions, and both axisymmetric and rectangular nozzle exit geometry are also accommodated. The induced suckdown flows are computed from the potential flowfield induced by the turbulent entrainment of both the free jets and wall jets in ground effect and from the free jets alone out of ground effect. The methodology emphasized geometric considerations, computation of stagnation lines and fountain upwash inclination, fountain upwash formation and development, and fountain impingement on the airframe.
    Keywords: AERODYNAMICS
    Type: AGARD Fluid Dyn. of Jets with Appl. to V(STOL; 20 p
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  • 124
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    Experimental determination of flow-interference effects of wing-mounted, two-dimensional, full-capture propulsion nacelles in close proximity to a vehicle body at a Mach number of 6 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Experimental tests have been conducted to determine possible aerodynamic interference effects due to the lateral positioning of two dimensional propulsion nacelles mounted on a wing surface in close proximity to a vehicle body. The tests were conducted at a Mach number of 6 and a Reynolds number 7 million per foot. The angle of attack range for force tests was -9 deg to 9 deg. The model configurations consisted of combinations of rectangular and trapezoidal cross section bodies with a wing swept 65 and a rectangular planform wing. A pair of two dimensional, flow through propulsion nacelles simulated full capture inlet operation.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83287 , L-15209 , NAS 1.15:83287
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  • 125
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    Wind-Tunnel/Flight Correlation, 1981 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Wind-tunnel/flight correlation activities are reviewed to assure maximum effectiveness of the early experimental programs of the National Transonic Facility (NTF). Topics included a status report of the NTF, the role of tunnel-to-tunnel correlation, a review of past flight correlation research and the resulting data base, the correlation potential of future flight vehicles, and an assessment of the role of computational fluid dynamics.
    Keywords: AERODYNAMICS
    Type: NASA-CP-2225 , L-15368 , NAS 1.55:2225
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  • 126
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    An analytical procedure for computing smooth transitions between two specified cross sections with applications to blended wing body configuration (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An analytical procedure is described for designing smooth transition surfaces for blended wing-body configurations. Starting from two specified cross section shapes, the procedure generates a gradual transition from one cross section shape to the other as an analytic blend of the two shapes. The method utilizes a conformal mapping, with subsequent translation and scaling, to transform the specified and shapes to curves that can be combined more smoothly. A sample calculation is applied to a blended wing-body missile type configuration with a top mounted inlet.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2012 , L-15053 , NAS 1.60:2012
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  • 127
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    Static internal performance of single expansion-ramp nozzles with thrust vectoring and reversing (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The effects of geometric design parameters on the internal performance of nonaxisymmetric single expansion-ramp nozzles were investigated at nozzle pressure ratios up to approximately 10. Forward-flight (cruise), vectored-thrust, and reversed-thrust nozzle operating modes were investigated.
    Keywords: AERODYNAMICS
    Type: NASA-TP-1962 , L-14902 , NAS 1.60:1962
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  • 128
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    Preliminary investigation of effects of heavy rain on the performance of aircraft (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A guideline was defined for the analysis of flight data to determine the effects of rain on the aerodynamic performance of an aircraft. It distinguishes and separates the effects of horizontal wind shears, downdrafts, gusts at the phugoid frequency, and rain based on various aerodynamic parameters. Flight data from NASA LaRC's TCV B-737 were inconclusive because precipitation rates encountered probably were not high enough. However, the guideline seemed to be valid and can be used on further flight data evaluations. Difficulties in this type of data analysis are discussed. Other indirect influences of rain on the degradation of airplane performance are also considered.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83272 , NAS 1.15:83272
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  • 129
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    Computation of transonic potential flow about 3 dimensional inlets, ducts, and bodies (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An analysis was developed and a computer code, P465 Version A, written for the prediction of transonic potential flow about three dimensional objects including inlet, duct, and body geometries. Finite differences and line relaxation are used to solve the complete potential flow equation. The coordinate system used for the calculations is independent of body geometry. Cylindrical coordinates are used for the computer code. The analysis is programmed in extended FORTRAN 4 for the CYBER 203 vector computer. The programming of the analysis is oriented toward taking advantage of the vector processing capabilities of this computer. Comparisons of computed results with experimental measurements are presented to verify the analysis. Descriptions of program input and output formats are also presented.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3514 , D6-49848
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  • 130
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    Transonic pressure measurements and comparison of theory to experiment for three arrow-wing configurations (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Wind tunnel tests of arrow-wing body configurations consisting of flat, twisted, and cambered twisted wings, as well as a variety of leading and trailing edge control surface deflections, were conducted at Mach numbers from 0.4 to 1.05 to provide an experimental pressure data base for comparison with theoretical methods. Theory to experiment comparisons of detailed pressure distributions were made using state of the art attached flow methods. Conditions under which these theories are valid for these wings are presented.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3434 , D6-51079-1
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  • 131
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    Transonic perturbation analysis of wing-fuselage-nacelle-pylon configurations with powered jet exhausts (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A method using a transonic small disturbance code with successive line over-relaxation is described for treating wing/fuselage configurations with a nacelle/pylon/powered jet. Examples illustrating its use for the NASA transport research model are given. Reasonable test/theory comparisons were obtained.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165852
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    Experimental study of delta wing leading-edge devices for drag reduction at high lift (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The drag reduction devices selected for evaluation were the fence, slot, pylon-type vortex generator, and sharp leading-edge extension. These devices were tested on a 60 degree flatplate delta (with blunt leading edges) in the Langley Research Center 7- by 10-foot high-speed tunnel at low speed and to angles of attack of 28 degrees. Balance and static pressure measurements were taken. The results indicate that all the devices had significant drag reduction capability and improved longitudinal stability while a slight loss of lift and increased cruise drag occurred.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165846
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  • 133
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    Spanwise loading distribution and wake velocity surveys of a semi-span wing (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The spanwise distribution of bound circulation on a semi-span wing and the flow velocities in its wake were measured in a wind tunnel. Particular attention was given to documenting the flow velocities in and around the development tip vortex. A two-component laser velocimeter was used to make the velocity measurements. The spanwise distribution of bound circulation, three components of the time-averaged velocities throughout the near wake their standard deviations, and the integrated forces and moments on a metric tip as measured by an internal strain gage balance are presented without discussion.
    Keywords: AERODYNAMICS
    Type: NASA-TM-84213 , A-8819 , USAAVRADCOM-TR-81-A-1
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  • 134
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    Noniterative grid generation using parabolic difference equations for fuselage-wing flow calculations (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A fast method for generating three-dimensional grids for fuselage-wing transonic flow calculations using parabolic difference equations is described. No iterative scheme is used in the three-dimensional sense; grids are generated from one grid surface to the next starting from the fuselage surface. The computational procedure is similar to the iterative solution of the two-dimensional heat conduction equation. The proposed method is at least 10 times faster than the elliptic grid generation method and has much smaller memory requirements. Results are presented for a fuselage and wing of NACA-0012 section and thickness ratio of 10 percent. Although only H-grids are demonstrated, the present technique should be applicable to C-grids and O-grids in three dimensions.
    Keywords: AERODYNAMICS
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  • 135
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    Implicit boundary conditions for the solution of the parabolized Navier-Stokes equations for supersonic flows (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Previously announced in STAR as N81-32875
    Keywords: AERODYNAMICS
    Type: (ISSN 0021-9991)
    Format: text
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  • 136
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    Summary of theoretical considerations and wind tunnel tests of an aerodynamic spoiler for stall proofing a general aviation airplane (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An airplane stall proofing system utilizing a spoiler was investigated for application on a low wing airplane representative of typical general aviation aircraft. Tests of the full scale airplane were conducted in the NASA Langley 30 x 60 foot full scale wind tunnel. The test velocity was 86 feet per second, corresponding to a Reynolds number of 2.20 million. The stall proofing capability of the spoiler is shown and a theoretical approach to the design of the spoiler and analysis of the spoiler's contribution to the airplane's trim and longitudinal stability is verified. Controlled spoiler deployment in a narrow angle of attack range, 4 degrees, immediately preceding the stall angle will stall proof the airplane. The results also show some of the limitations of flight tests to determine spoiler deployment rate for good handling qualities.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165100
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  • 137
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    CAS22 - FORTRAN program for fast design and analysis of shock-free airfoil cascades using fictitious-gas concept (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A user-oriented computer program, CAS22, was developed that is applicable to aerodynamic analysis and transonic shock-free redesign of existing two-dimensional cascades of airfoils. This FORTRAN program can be used: (1) as an analysis code for full-potential, transonic, shocked or shock-free cascade flows; (2) as a design code for shock-free cascades that uses Sobieczky's fictitious-gas concept; and (3) as a shock-free design code followed automatically by the analysis in order to confirm that the newly obtained cascade shape provides for an entirely shock-free transonic flow field. A four-level boundary-conforming grid of an O type is generated. The shock-free design is performed by implementing Sobieczky's fictitious-gas concept of elliptic continuation from subsonic into supersonic flow domains. Recomputation inside each supersonic zone is performed by the method of characteristics in the rheograph plane by using isentropic gas relations. Besides converting existing cascade shapes with multiple shocked supersonic regions into shock-free cascades, CAS22 can also unchoke previously choked cascades and make them shock free.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3507
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  • 138
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    V/STOL Tandem Fan transition section model test (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An approximately 0.25 scale model of the transition section of a tandem fan variable cycle engine nacelle was tested in the NASA Lewis Research Center 10-by-10 foot wind tunnel. Two 12-inch, tip-turbine driven fans were used to simulate a tandem fan engine. Three testing modes simulated a V/STOL tandem fan airplane. Parallel mode has two separate propulsion streams for maximum low speed performance. A front inlet, fan, and downward vectorable nozzle forms one stream. An auxilliary top inlet provides air to the aft fan - supplying the core engine and aft vectorable nozzle. Front nozzle and top inlet closure, and removal of a blocker door separating the two streams configures the tandem fan for series mode operations as a typical aircraft propulsion system. Transition mode operation is formed by intermediate settings of the front nozzle, blocker door, and top inlet. Emphasis was on the total pressure recovery and flow distortion at the aft fan face. A range of fan flow rates were tested at tunnel airspeeds from 0 to 240 knots, and angles-of-attack from -10 to 40 deg for all three modes. In addition to the model variables for the three modes, model variants of the top inlet were tested in the parallel mode only. These lip variables were: aft lip boundary layer bleed holes, and Three position turning vane. Also a bellmouth extension of the top inlet side lips was tested in parallel mode.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165587 , NAS 1.26:165587 , TR2-53200/2R-53085
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  • 139
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    Survey of engineering computational methods and experimental programs for estimating supersonic missile aerodynamic characteristics (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-07-27
    Description: This paper presents a survey of engineering computational methods and experimental programs used for estimating the aerodynamic characteristics of missile configurations. Emphasis is placed on those methods which are suitable for preliminary design of conventional and advanced concepts. An analysis of the technical approaches of the various methods is made in order to assess their suitability to estimate longitudinal and/or lateral-directional characteristics for different classes of missile configurations. Some comparisons between the predicted characteristics and experimental data are presented. These comparisons are made for a large variation in flow conditions and model attitude parameters. The paper also presents known experimental research programs developed for the specific purpose of validating analytical methods and extending the capability of data-base programs.
    Keywords: AERODYNAMICS
    Type: Symposium on Missile Aerodynamics; Sept. 20-22, 1982; Trondheim; Norway
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  • 140
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    Thrust-induced effects on low-speed aerodynamics of fighter aircraft (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Results of NASA Langley has conducted wind-tunnel investigations of several fighter configurations conducted to determine the effects of both thrust vectoring and spanwise blowing are reviewed. A recent joint NASA/Grumman Aerospace Corporation/U.S. Air Force Wright Aeronautical Laboratory wind-tunnel investigation was conducted to examine the effects of spanwise blowing on the trailing-edge flap system. This application contrasts with the more familiar method of spanwise blowing near the wing leading edge. Another joint program among NASA/McDonnell Aircraft Company/U.S. Air Force Wright Aeronautical Laboratory investigated the effects of reverse thrust on the low-speed aerodynamics of an F-15 configuration. The F-15 model was fitted with a rotating van thrust reverser concept which could simulate both in-flight reversing for approach and landing or full reversing for ground roll reduction. The significant results of these two joint programs are reported.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83277 , NAS 1.15:83277
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  • 141
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    Water tunnel flow visualization and wind tunnel data analysis of the F/A-18 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Six degree of freedom studies were utilized to extract a band of yawing and rolling moment coefficients from the F/A-18 aircraft flight records. These were compared with 0.06 scale model data obtained in a 16T wind tunnel facility. The results, indicate the flight test yawing moment data exhibit an improvement over the wind tunnel data to near neutral stability and a significant reduction in lateral stability (again to anear neutral level). These data are consistent with the flight test results since the motion was characterized by a relatively slo departure. Flight tests repeated the slow yaw departure at M 0.3. Only 0.16 scale model wind tunnel data showed levels of lateral stability similar to the flight test results. Accordingly, geometric modifications were investigated on the 0.16 scale model in the 30x60 foot wind tunnel to improve high angle of attack lateral stability.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165859 , NAS 1.26:165859
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  • 142
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    Production version of the extended NASA-Langley Vortex Lattice FORTRAN computer program. Volume 1: User's guide (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The latest production version, MARK IV, of the NASA-Langley vortex lattice computer program is summarized. All viable subcritical aerodynamic features of previous versions were retained. This version extends the previously documented program capabilities to four planforms, 400 panels, and enables the user to obtain vortex-flow aerodynamics on cambered planforms, flowfield properties off the configuration in attached flow, and planform longitudinal load distributions.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83303 , NAS 1.15:83303
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  • 143
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    Subsonic aerodynamic and flutter characteristics of several wings calculated by the SOUSSA P1.1 panel method (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The SOUSSA (steady, oscillatory, and unsteady subsonic and supersonic aerodynamics) program is the computational implementation of a general potential flow analysis (by the Green's function method) that can generate pressure distributions on complete aircraft having arbitrary shapes, motions and deformations. Some applications of the initial release version of this program to several wings in steady and oscillatory motion, including flutter are presented. The results are validated by comparisons with other calculations and experiments. Experiences in using the program as well as some recent improvements are described.
    Keywords: AERODYNAMICS
    Type: NASA-TM-84485 , NAS 1.15:84485
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  • 144
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    Elastic deformation effects on aerodynamic characteristics for a high-aspect-ratio supercritical-wing model (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The results of an investigation of the deformations of a high-aspect-ratio, force/pressure, supercritical-wing model during wind tunnel tests and the effects these deformations have on the wing aerodynamics are presented. A finite element model of the wing was developed, and then, for conditions corresponding to wind tunnel test points, experimental aerodynamic loads and theoretical aerodynamic loads were applied to the finite element model. Comparisons were made between the results of these load conditions for changes in structural deflections and for changes in aerodynamic characteristics. The results show that the deformations are quite small and that the pressure data are not significantly affected by model deformation.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83286 , L-15098 , NAS 1.15:83286
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  • 145
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    A harmonic analysis method for unsteady transonic flow and its application to the flutter of airfoils (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A finite difference method for solving the unsteady transonic flow about harmonically oscillating wings is investigated. The procedure is based on separating the velocity potential into steady and unsteady parts and linearizing the resulting unsteady differential equation for small disturbances. The differential equation for the unsteady velocity potential is linear with spatially varying coefficients and with the time variable eliminated by assuming harmonic motion. A study is presented of the shock motion associated with an oscillating airfoil and its representation by the harmonic procedure. The effects of the shock motion and the resulting pressure pulse are shown to be included in the harmonic pressure distributions and the corresponding generalized forces. Analytical and experimental pressure distributions for the NACA 64A010 airfoil are compared for Mach numbers of 0.75, 0.80 and 0.842. A typical section, two-degree-of-freedom flutter analysis of a NACA 64A010 airfoil is performed. The results show a sharp transonic bucket in one case and abrupt changes in instability modes.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3537 , NAS 1.26:3537 , D6-49821
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  • 146
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    An assessment of a modified potential flow code for calculating the effect of small geometric change on the pressure and forces of supercritical airfoils (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Wind-tunnel test data for two closely related supercritical airfoils were compared with calculations obtained from a nonconservative, potential flow code over a Mach number range from 0.20 to 0.80. The potential flow code includes an iterated, integral boundary-layer correction. The theoretical pressure distributions correlated more closely with the experimental pressure distributions when the flow was entirely subsonic or subsonic with a small supersonic zone than when the flow contained a large supersonic zone. The predicted drag level was below the experimental values at nearly all test conditions and the difference in drag level for the two airfoils was not accurately predicted.
    Keywords: AERODYNAMICS
    Type: NASA-TM-84227 , A-8861 , NAS 1.15:84227
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  • 147
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    Feasibility of observer system for determining orientation of balloon borne observational platforms (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The instantaneous orientation (i.e., the attitude) of the LACATE instrumentation platform with respect to a local vertical is discussed. An observer model for predicting the orientation of balloon-borne research platforms is described. Determination of the platform orientation as a function of time is addressed.
    Keywords: AERODYNAMICS
    Type: NASA-CR-168945 , NAS 1.26:168945
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  • 148
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    Effect of wind gusts on the motion of a balloon-borne observation platform (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The effect of wind gusts on the magnitude of the pendulation angles of a balloon-borne observation platform is determined. A system mathematical model is developed and the solution of this model is used to determine the magnitude of the observation platforms pendulation angles.
    Keywords: AERODYNAMICS
    Type: NASA-CR-168947 , NAS 1.26:168947
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  • 149
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    Rotary balance data for an F-15 model with conformal fuel tanks for an angle-of-attack range of 8 deg to 90 deg (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Aerodynamic characteristics obtained in a rotational flow environment, utilizing a rotary balance, are presented in plotted form for a 1/12 scale conformal fuel tank equipped F-15 airplane model. The configurations tested included in the buildup of airplane components and the basic airplane with various control deflections. Data are presented for all configurations without analysis for an angle of attack range of 8 to 90 deg, and clockwise and counterclockwise rotations covering an omega b/2V range from 0 to 0.4. Selected configurations are presented over an extended omega b/2V range from 0 to 0.9.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3516 , NAS 1.26:3516
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  • 150
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    F-15 rotary balance data for an angle-of-attack range of 8 deg to 90 deg (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Aerodynamic characteristics obtained in a rotational flow environment, utilizing a rotary balance are presented in plotted form for a 1/12 scale F-15 airplane model. The configurations tested included the buildup of airplane components and the basic airplane with various control deflections. Data are presented for all configurations without analysis for an angle of attack range of 8 to 90 deg, and clockwise and counterclockwise rotations covering an omega b/2V range from 0 to 0.4. Selected configurations are presented over an extended omega b/2V range from 0 to 0.9.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3478 , NAS 1.26:3478
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  • 151
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    Three-dimensional separation and reattachment (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    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 construed 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: NASA-TM-84221 , A-8845 , NAS 1.15:84221
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  • 152
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    Rime ice accretion and its effect on airfoil performance (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A methodology was developed to predict the growth of rime ice, and the resulting aerodynamic penalty on unprotected, subcritical, airfoil surfaces. The system of equations governing the trajectory of a water droplet in the airfoil flowfield is developed and a numerical solution is obtained to predict the mass flux of super cooled water droplets freezing on impact. A rime ice shape is predicted. The effect of time on the ice growth is modeled by a time-stepping procedure where the flowfield and droplet mass flux are updated periodically through the ice accretion process. Two similarity parameters, the trajectory similarity parameter and accumulation parameter, are found to govern the accretion of rime ice. In addition, an analytical solution is presented for Langmuir's classical modified inertia parameter. The aerodynamic evaluation of the effect of the ice accretion on airfoil performance is determined using an existing airfoil analysis code with empirical corrections. The change in maximum lift coefficient is found from an analysis of the new iced airfoil shape. The drag correction needed due to the severe surface roughness is formulated from existing iced airfoil and rough airfoil data. A small scale wind tunnel test was conducted to determine the change in airfoil performance due to a simulated rime ice shape.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165599 , NAS 1.26:165599
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  • 153
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    Experimental and analytical results of tangential blowing applied to a subsonic V/STOL inlet (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Engine inlets for subsonic V/STOL aircraft must operate over a wide range of conditions without internal flow separation. Experimental and analytical investigations were conducted to evaluate the effectiveness of tangential blowing to maintain attached flow to high angles of attack. The inlet had a relatively thin lip with a blowing slot located either on the lip or in the diffuser. The height and width of these slots was varied. Experimentally determined flow separation boundaries showed that lip blowing achieved higher angle of attack capability than diffuser blowing. This capability was achieved with the largest slot circumferential extent and either of the two slot heights. Predicted (analytical) separation boundaries showed good agreement except at the highest angles of attack.
    Keywords: AERODYNAMICS
    Type: NASA-TM-82847 , E-1217 , NAS 1.15:82847
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  • 154
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    Static and unsteady pressure measurements on a 50 degree clipped delta wing at M = 0.9 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Pressures were measured with Freon as the test medium. Data taken at M = 0.9 is presented for static and oscillatory deflections of the trailing edge control surface and for the wing in pitch. Comparisons of the static measured data are made with results computed using the Bailey-Ballhaus small disturbance code.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83297 , NAS 1.15:83297
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  • 155
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    A flight investigation of blade-section aerodynamics for a helicopter main rotor having RC-SC2 airfoil sections (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Pressure data at 90 percent blade radius for a helicopter main rotor with RC-SC2 blade sections was obtained. Concurrent measurements were made of vehicle flight state, performance and some rotor loads. The test envelope included hover, level flight from about 65 to 144 knots, climb and descent, and collective fixed maneuvers. Airfoil pressure distributions obtained in flight agree with those theoretical calculations for two dimensional, steady flow.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83298 , NAS 1.15:83298
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  • 156
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    Effect of nacelles on aerodynamic characteristics of an executive-jet model with simulated, partial-chord, laminar-flow-control wing glove (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Tests were conducted in the Langley High-Speed 7- by 10-Foot Tunnel using a 1/10-scale model of an executive jet to examine the effects of the nacelles on the wing pressures and model longitudinal aerodynamic characteristics. For the present investigation, each wing panel was modified with a simulated, partial-chord, laminar-flow-control glove. Horizontal-tail effects were also briefly examined. The tests covered a range of Mach numbers from 0.40 to 0.82 and lift coefficients from 0.20 to 0.55. Oil-flow photographs of the wing at selected conditions are included.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83271 , L-14982 , NAS 1.15:83271
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  • 157
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    A variational principle for compressible fluid mechanics. Discussion of the one-dimensional theory (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The second law of thermodynamics is used as a variational statement to derive a numerical procedure to satisfy the governing equations of motion. The procedure, based on numerical experimentation, appears to be stable provided the CFL condition is satisfied. This stability is manifested no matter how severe the gradients (compression or expansion) are in the flow field. For reasons of simplicity only one dimensional inviscid compressible unsteady flow is discussed here; however, the concepts and techniques are not restricted to one dimension nor are they restricted to inviscid non-reacting flow. The solution here is explicit in time. Further study is required to determine the impact of the variational principle on implicit algorithms.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3526 , NAS 1.26:3526 , CI-TR-0042
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  • 158
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    Effects of axisymmetric and normal air jet plumes and solid plume on cylindrical afterbody pressure distributions at Mach numbers from 1.65 to 2.50 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A wind tunnel investigation of the interference effects of axisymmetric nozzle air plumes, a solid plume, and normal air jet plumes on the afterbody pressure distributions and base pressures of a cylindrical afterbody model was conducted at Mach numbers from 1.65 to 2.50. The axisymmetric nozzles, which varied in exit lip Mach number from 1.7 to 2.7, and the normal air jet nozzle were tested at jet pressure ratios from 1 (jet off) to 615. The tests were conducted at an angle of attack of 0 deg and a Reynolds number per meter of 6.56 million. The results of the investigation show that the solid plume induces greater interference effects than those induced by the axisymmetric nozzle plumes at the selected underexpanded design conditions. A thrust coefficient parameter based on nozzle lip conditons was found to correlate the afterbody disturbance distance and the base pressure between the different axisymmetric nozzles. The normal air jet plume and the solid plume induce afterbody disturbance distances similar to those induced by the axisymmetric air plumes when base pressure is held constant.
    Keywords: AERODYNAMICS
    Type: NASA-TP-2005 , L-14883 , NAS 1.60:2005
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  • 159
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    Analysis of rotary balance data for the F-15 airplane including the effect of conformal fuel tanks (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: F-15 rotary balance data was analyzed, and the influence of control deflections, Reynolds number and airplane components, i.e., body, wing, horizontal and vertical tails, as well as conformal tanks, on the aerodynamics up to 90 degrees angle of attack are discussed. Steady state spin mode predictions using these data are presented, which show excellent correlation with spin tunnel and flight test results. Generally, the data shows damped yawing moment slopes with rotation at all angles of attack, and good control effectiveness. Differences in the rotary aerodynamics due to the addition of conformal tanks are minimal. The small differences in the region of the flat spin do, however, indicate that the resulting spin mode would be slightly flatter and faster for a conformal tank equipped airplane. The addition of conformal tanks make the airplane more departure susceptible.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3479 , NAS 1.26:3479
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  • 160
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    Development of a locally mass flux conservative computer code for calculating 3-D viscous flow in turbomachines (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The VANS successive approximation numerical method was extended to the computation of three dimensional, viscous, transonic flows in turbomachines. A cross-sectional computer code, which conserves mass flux at each point of the cross-sectional surface of computation was developed. In the VANS numerical method, the cross-sectional computation follows a blade-to-blade calculation. Numerical calculations were made for an axial annular turbine cascade and a transonic, centrifugal impeller with splitter vanes. The subsonic turbine cascade computation was generated in blade-to-blade surface to evaluate the accuracy of the blade-to-blade mode of marching. Calculated blade pressures at the hub, mid, and tip radii of the cascade agreed with corresponding measurements. The transonic impeller computation was conducted to test the newly developed locally mass flux conservative cross-sectional computer code. Both blade-to-blade and cross sectional modes of calculation were implemented for this problem. A triplet point shock structure was computed in the inducer region of the impeller. In addition, time-averaged shroud static pressures generally agreed with measured shroud pressures. It is concluded that the blade-to-blade computation produces a useful engineering flow field in regions of subsonic relative flow; and cross-sectional computation, with a locally mass flux conservative continuity equation, is required to compute the shock waves in regions of supersonic relative flow.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3539 , NAS 1.26:3539 , SR-34
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    Design of supercritical cascades with high solidity (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The method of complex characteristics of Garabedian and Korn was successfully used to design shockless cascades with solidities of up to one. A code was developed using this method and a new hodograph transformation of the flow onto an ellipse. This code allows the design of cascades with solidities of up to two and larger turning angles. The equations of potential flow are solved in a complex hodograph like domain by setting a characteristic initial value problem and integrating along suitable paths. The topology that the new mapping introduces permits a simpler construction of these paths of integration.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165600 , NAS 1.26:165600
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  • 162
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    Aerodynamic analysis of VTOL inlets and definition of a short, blowing-lip inlet (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The results indicated that, without boundary layer control, either a very long inlet or an inlet with a very high contraction ratio lip will be required to meet the stringent design requirements. It is shown that active boundary layer control is an effective means of preventing separation and that a significant reduction in inlet size can be achieved by removing only a small amount of bleed in the throat region of the inlet. A short, blowing-lip model was designed and fabricated. This model features an adjustable, blowing slot located near the hilite on the windward side of the inlet.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165617 , NAS 1.26:165617 , D6-51418
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  • 163
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    Wind-tunnel investigation of the powered low-speed longitudinal aerodynamics of the Vectored-Engine-Over (VEO) wing fighter configuration (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A wind-tunnel investigation incorporating both static and wind-on testing was conducted in the Langley 4- by 7-Meter Tunnel to determine the effects of vectored thrust along with spanwise blowing on the low-speed aerodynamics of an advanced fighter configuration. Data were obtained over a large range of thrust coefficients corresponding to takeoff and landing thrust settings for many nozzle configurations. The complete set of static thrust data and the complete set of longitudinal aerodynamic data obtained in the investigation are presented. These data are intended for reference purposes and, therefore, are presented without analysis or comment. The analysis of the thrust-induced effects found in the investigation are not discussed.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83263 , NAS 1.15:83263
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  • 164
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    Stability of boundary layers with porous suction strips: Experiment and theory (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Low turbulence tunnel experiments on the stability and transition of 2 D boundary layers on flat plates with and without suction are described. A number of general suction cases are discussed. Test results showed that the maximum stabilization occurred when the suction was moved toward the Branch I neutral point. An analytical study of the stability of two dimensional, incompressible boundary layer flows over plates with suction through porous strips was performed. The mean flow was calculated using linearized triple deck, closed form solutions. The stability results of the triple deck theory are shown to be in good agreement with those of the interacting boundary layers. An analytical optimization scheme for the suction configuration was developd. Numerical calculations were performed corresponding to the experimental configurations. In each case, the theory correctly predicts the experimental results.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center Laminar Flow Control; p 63-74
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  • 165
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    Procedures for the computation of unsteady transonic flows including viscous effects (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Modifications of the code LTRAN2, developed by Ballhaus and Goorjian, which account for viscous effects in the computation of planar unsteady transonic flows are presented. Two models are considered and their theoretical development and numerical implementation is discussed. Computational examples employing both models are compared with inviscid solutions and with experimental data. Use of the modified code is described.
    Keywords: AERODYNAMICS
    Type: NASA-CR-166249 , NAS 1.26:166249
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  • 166
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    Effects of installation of F101 DFE exhaust nozzles on the afterbody-nozzle characteristics of the F-14 airplane (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A wind-tunnel investigation was conducted to determine the effects of F101 DFE (derivative fighter engine) nozzle axial positioning on the afterbody-nozzle longitudinal aerodynamic characteristics of the F-14 airplane. The model was tested in the Langley 16-Foot Transonic Tunnel at Mach numbers from 0.7 to 1.25 and angles of attack from about -2 to 6 degrees. Compressed air was used to simulate nozzle exhaust flow at jet total-pressure ratios from 1 (jet off) to about 8. The results of the investigation show that for subsonic Mach numbers the intermediate cruise nozzle position of the three positions tested resulted in the lowest drag.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83250 , L-14895
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  • 167
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    Subsonic panel method for the efficient analysis of multiple geometry perturbations (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An accurate and efficient method was developed for the aerodynamic analysis of a series of arbitrary small geometry perturbations to a given baseline configuration. The method is appropriate for wing-fuselage configurations in incompressible potential flow. Mathematical formulations are presented for three computer programs that are employed. The first program is a conventional surface panel method for calculating the baseline singularity distribution. The second program calculates a partial derivative matrix. Each element of the matrix is the rate of change of singularity strength at one point with respect to a surface coordinate of a different point. For each baseline configuration, the calculated quantities from the first two programs establish an input file for the third. The third program calculates the surface pressure distribution and forces and moments for a series of geometry perturbations.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3528
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  • 168
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    Evaluation of wind tunnel performance testings of an advanced 45 deg swept 8-bladed propeller at Mach numbers from 0.45 to 0.85 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The increased emphasis of fuel conservation in the world and the rapid increase in the cost of jet fuel has stimulated a series of studies of both conventional and unconventional propulsion systems for commercial aircraft. The results of these studies indicate that a fuel saving of 15 to 30 percent may be realized by the use of an advanced high-speed turboprop (Prop-Fan) compared to aircraft equipped with high bypass turbofan engines of equivalent technology. The Prop-Fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficient Program. This effort includes the wind tunnel testing of a series of 8 and 10-blade Prop-Fan models incorporate swept blades. Test results indicate efficiency levels near the goal of 80 percent at Mach 0.8 cruise and an altitude of 10.67 km (35,000 ft). Each successive swept model has shown improved efficiency relative to the straight blade model. The fourth model, with 45 deg swept blades reported herein, shows a net efficiency of 78.2 at the design point with a power loading of 301 kW/sq meter and a tip speed of 243.8 m/sec (800 ft/sec.).
    Keywords: AERODYNAMICS
    Type: NASA-CR-3505
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  • 169
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    RAXJET: A computer program for predicting transonic, axisymmetric flow over nozzle afterbodies with supersonic jet exhausts (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A viscous-inviscid interaction method to calculate the subsonic and transonic flow over nozzle afterbodies with supersonic jet exhausts was developed. The method iteratively combines a relaxation solution of the full potential equation for the inviscid external flow, a shock capturing-shock fitting inviscid jet solution, an integral boundary layer solution, a control volume method for treating separated flows, and an overlaid mixing layer solution. A computer program called RAXJET which incorporates the method, illustrates the predictive capabilities of the method by comparison with experimental data is described, a user's guide to the computer program is provided. The method accurately predicts afterbody pressures, drag, and flow field properties for attached and separated flows for which no shock induced separation occurs.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83235 , L-14789
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  • 170
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    Application of an airfoil stall flutter computer prediction program to a three-dimensional wing: Prediction versus experiment (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An aerodynamic computer code, capable of predicting unsteady and C sub m values for an airfoil undergoing dynamic stall, is used to predict the amplitudes and frequencies of a wing undergoing torsional stall flutter. The code, developed at United Technologies Research Corporation (UTRC), is an empirical prediction method designed to yield unsteady values of normal force and moment, given the airfoil's static coefficient characteristics and the unsteady aerodynamic values, alpha, A and B. In this experiment, conducted in the PSU 4' x 5' subsonic wind tunnel, the wing's elastic axis, torsional spring constant and initial angle of attack are varied, and the oscillation amplitudes and frequencies of the wing, while undergoing torsional stall flutter, are recorded. These experimental values show only fair comparisons with the predicted responses. Predictions tend to be good at low velocities and rather poor at higher velocities.
    Keywords: AERODYNAMICS
    Type: NASA-CR-168586
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  • 171
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    A vortex-filament and core model for wings with edge vortex separation (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A vortex filament-vortex core method for predicting aerodynamic characteristics of slender wings with edge vortex separation was developed. Semi-empirical but simple methods were used to determine the initial positions of the free sheet and vortex core. Comparison with available data indicates that: (1) the present method is generally accurate in predicting the lift and induced drag coefficients but the predicted pitching moment is too positive; (2) the spanwise lifting pressure distributions estimated by the one vortex core solution of the present method are significantly better than the results of Mehrotra's method relative to the pressure peak values for the flat delta; (3) the two vortex core system applied to the double delta and strake wings produce overall aerodynamic characteristics which have good agreement with data except for the pitching moment; and (4) the computer time for the present method is about two thirds of that of Mehrotra's method.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165847
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  • 172
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    Numerical analysis and FORTRAN program for the computation of the turbulent wakes of turbomachinery rotor blades, isolated airfoils and cascade of airfoils (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Turbulent wakes of turbomachinery rotor blades, isolated airfoils, and a cascade of airfoils were investigated both numerically and experimentally. Low subsonic and incompressible wake flows were examined. A finite difference procedure was employed in the numerical analysis utilizing the continuity, momentum, and turbulence closure equations in the rotating, curvilinear, and nonorthogonal coordinate system. A nonorthogonal curvilinear coordinate system was developed to improve the accuracy and efficiency of the numerical calculation. Three turbulence models were employed to obtain closure of the governing equations. The first model was comprised to transport equations for the turbulent kinetic energy and the rate of energy dissipation, and the second and third models were comprised of equations for the rate of turbulent kinetic energy dissipation and Reynolds stresses, respectively. The second model handles the convection and diffusion terms in the Reynolds stress transport equation collectively, while the third model handles them individually. The numerical results demonstrate that the second and third models provide accurate predictions, but the computer time and memory storage can be considerably saved with the second model.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3509 , PSU/TURBO-81-4
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  • 173
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    Spin-tunnel investigation of a 1/13-scale model of the NASA AD-1 oblique-wing research aircraft (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The spin and recovery characteristics of a 1/13-scale model of the NASA AD-1 oblique-wing research aircraft at wing-skew positions of 0, 25, 45, and 60 deg (right wing forward) were investigated. Spins were obtained for all wing-skew positions tested. For the unskewed wing position, two spin modes were possible. One spin mode was very steep and recoveries were obtained within 1 turn or less by rudder reversal. The second spin mode was flat and fast; the angle of attack was about 75 deg and the spin rate was about 145 deg/sec (2.5 seconds per turn). For the skewed wing positions, spins were obtained only in the direction of the forward-skewed wing (right wing forward). No spins were obtained to the left when the wing was skewed with the right wing forward. Recoveries should be attempted by deflecting the rudder to full against the spin, the ailerons to full with the spin, and movement of the wings to 0 deg skew. If the wing is skewed, the recovery may not be effected until the wing skew approaches 0 deg.
    Keywords: AERODYNAMICS
    Type: NASA-TM-83236 , L-14834
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  • 174
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    An analytical investigation of the free-tip rotor for helicopters (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A rotor configuration called the free-tip rotor was analytically investigated for its potential to improve helicopter forward-flight performance characteristics. This rotor differs from a conventional rotor only in the blade tip region. In this configuration, the tip is self-adjusting in pitch with respect to the rest of the blade, in accordance with a moment balance about its pitch axis. With this self-adjusting capability, the resulting pitch motion generates a more uniform airload distribution around the azimuth. Computer math models were used to compare performance characteristics of the free tip rotor with those of a conventional rotor operation at flight speeds from 130 to 160 knots. The results of this analysis indicate that the free-tip rotor improves cruise lift-drag ratio by at least 22%.
    Keywords: AERODYNAMICS
    Type: NASA-TM-81345 , A-8806
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  • 175
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    Tests of a D vented thrust deflecting nozzle behind a simulated turbofan engine (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A D vented thrust deflecting nozzle applicable to subsonic V/STOL aircraft was tested behind a simulated turbofan engine in the verticle thrust stand. Nozzle thrust, fan operating characteristics, nozzle entrance conditions, and static pressures were measured. Nozzle performance was measured for variations in exit area and thrust deflection angle. Six core nozzle configurations, the effect of core exit axial location, mismatched core and fan stream nozzle pressure ratios, and yaw vane presence were evaluated. Core nozzle configuration affected performance at normal and engine out operating conditions. Highest vectored nozzle performance resulted for a given exit area when core and fan stream pressure were equal. Its is concluded that high nozzle performance can be maintained at both normal and engine out conditions through control of the nozzle entrance Mach number with a variable exit area.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3508 , MDC-A6930
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  • 176
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    Inlet and airframe compatibility for a V/STOL fighter/attack aircraft with top-mounted inlets (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Aerodynamic force and inlet pressure data are obtained for 9.5% force and pressure models of a V/STOL fighter/attack aircraft configuration with top mounted twin inlets. Data are presented from tests conducted in the Ames Unitary Wind Tunnels at Mach numbers of 0.6, 0.9, and 1.2 at angles of attack up to 27 deg. and angles of sideslip up to 12 deg. Trimmed aerodynamic characteristics and inlet performance are compared for three different leading edge extension (LEX) configurations. The effects of wing leading and trailing-edge flaps on the inlet are also determined. Maneuver perfromance is calculated form combined force and inlet pressure data. The largest of the three LEX sizes tested gives the best airplane maneuver performance. Wing flap deflections improved inlet recovery at all Mach numbers.
    Keywords: AERODYNAMICS
    Type: NASA-TM-84252 , A-8948 , NAS 1.15:84252
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  • 177
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    Free Wake Techniques for Rotor Aerodynamic Analysis. Volume 3: Vortex Filament Models (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Results obtained using a vortex filament model, as opposed to sheets are discussed, against using various modeling techniques and including the computer codings.
    Keywords: AERODYNAMICS
    Type: NASA-CR-166436 , NAS 1.26:166436 , ASRL-TR-199-3
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  • 178
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    Free Wake Techniques for Rotor Aerodynamic Analysis. Volume 1: Summary of Results and Background Theory (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Results obtained during the development of a consistent aerodynamic theory for rotors in hovering flight are discussed. Methods of aerodynamic analysis were developed which are adequate for general design purposes until such time as more elaborate solutions become available, in particular solutions which include real fluids effects. Several problems were encountered in the course of this development, and many remain to be solved, however it is felt that a better understanding of the aerodynamic phenomena involved was obtained. Remaining uncertainties are discussed.
    Keywords: AERODYNAMICS
    Type: NASA-CR-166434 , NAS 1.26:166434 , ASRL-TR-199-1
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  • 179
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    Aerodynamic data from a two-dimensional cambered airfoil section in a shallow transonic flexible walled test section (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Further flexible wall technique validation in two dimensional testing was carried out with the transonic self streamlining wind tunnel (TSWT) using a cambered NPL 9510 section.
    Keywords: AERODYNAMICS
    Type: NASA-CR-166005 , NAS 1.26:166005 , AASU-MEMO-82/7
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  • 180
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    Mean-flow measurements of the flow field diffusing bend (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Time-average measurements of the low-speed turbulent flow in a diffusing bend are presented. The experimental geometry consists of parallel top and bottom walls and curved diverging side walls. The turning of the center line of this channel is 40 deg, the area ratio is 1.5 and the ratios of height and center-line length to throat width are 1.5 and 3, respectively. The diffusing bend is preceded and followed by straight constant area sections. The inlet boundary layers on the parallel walls are artificially thickened and occupy about 30% of the channel height; those on the side walls develop naturally and are about half as thick. The free-stream speed at the inlet was approximately 30 m/sec for all the measurements. Inlet boundary layer mean velocity and turbulence intensity profiles are presented, as are data for wall static pressures, and at six cross sections, surveys of the velocity-vector and static-pressure fields. The dominant feature of the flow field is a pair of counter-rotating streamwise vortices formed by the cross-stream pressure gradient in the bend on which an overall deceleration is superimposed.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3634 , NAS 1.26:3624 , NEAR-TR-271 , NAS 1.26:3634
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  • 181
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    Supersonic wing-body center of pressure with finite afterbodies (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Closed-form formulas for the effects of finite afterbodies on the longitudinal center of pressure location in the presence of a wing at supersonic speeds are presented, along with solutions for the case of negative afterbodies. A double integral is developed for the case of subsonic and supersonic leading edges and no afterbody and full afterbody. Attention is also given to the full/infinite body case, noting that a proportional variation of the pitching moment with the lift is found.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 20; Aug. 198
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  • 182
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    Experiments on the flow and acoustic properties of a moderate-Reynolds-number supersonic jet (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Flow and acoustic properties of a jet at Reynolds number of 70,000 were studied at Mach 2.1. Measurements in a free jet test facility were made with pitot tubes and hot-wire anemometry. Center-line Mach number distributions for natural and excited jets were obtained. A slow initial growth rate was in the potential core region of the jet, indicating a transition from laminar to turbulent flow in moderate Reynolds number jets. The transition occurred within the first 2-3 diameters. Spectral components were calculated for the fluctuating flowfield, and sound pressure levels were measured for the overall near-field noise. The centroid of noise was located about 8 nozzle diameters downstream. The growth rates of instabilities were determined to be in agreement with linear stability theory predictions over a broad frequency range.
    Keywords: AERODYNAMICS
    Type: Journal of Fluid Mechanics; 116; Mar. 198
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  • 183
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    Computer prediction of three-dimensional potential flow fields in which aircraft propellers operate (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A computer program was developed to calculate the three dimensional, steady, incompressible, inviscid, irrotational flow field at the propeller plane (propeller removed) located upstream of an arbitrary airframe geometry. The program uses a horseshoe vortex of known strength to model the wing. All other airframe surfaces are modeled by a network source panels of unknown strength which is exposed to a uniform free stream and the wing-induced velocity field. By satisfying boundary conditions on each panel (the Neumann problem), relaxed boundary conditions being used on certain panels to simulate inlet inflow, the source strengths are determined. From the known source and wing vortex strengths, the resulting velocity fields on the airframe surface and at the propeller plane are obtained. All program equations are derived in detail, and a brief description of the program structure is presented. A user's manual which fully documents the program is cited. Computer predictions of the flow on the surface of a sphere and at a propeller plane upstream of the sphere are compared with the exact mathematical solutions. Agreement is good, and correct program operation is verified.
    Keywords: AERODYNAMICS
    Type: NASA-CR-169317 , NAS 1.26:169317
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  • 184
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    An experimental study of dynamic stall on advanced airfoil sections. Volume 1: Summary of the experiment (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The static and dynamic characteristics of seven helicopter sections and a fixed-wing supercritical airfoil were investigated over a wide range of nominally two dimensional flow conditions, at Mach numbers up to 0.30 and Reynolds numbers up to 4 x 10 to the 6th power. Details of the experiment, estimates of measurement accuracy, and test conditions are described in this volume (the first of three volumes). Representative results are also presented and comparisons are made with data from other sources. The complete results for pressure distributions, forces, pitching moments, and boundary-layer separation and reattachment characteristics are available in graphical form in volumes 2 and 3. The results of the experiment show important differences between airfoils, which would otherwise tend to be masked by differences in wind tunnels, particularly in steady cases. All of the airfoils tested provide significant advantages over the conventional NACA 0012 profile. In general, however, the parameters of the unsteady motion appear to be more important than airfoil shape in determining the dynamic-stall airloads.
    Keywords: AERODYNAMICS
    Type: NASA-TM-84245-VOL-1 , A-8924 , NAS 1.15:84245-Vol-1 , USAAVRADCOM-TR-82-A-8-Vol-1
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  • 185
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    Three dimensional flow measurements in a turbine scroll (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A study was conducted to determine experimentally the flow behavior in combined scroll nozzle assembly of a radial inflow turbine. Hot film anemometry technique was used to measure the three dimensional flow velocity in the scroll. The through flow and secondary flow velocity components are measured at various points in three scroll sections.
    Keywords: AERODYNAMICS
    Type: NASA-CR-167920 , NAS 1.26:167920
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  • 186
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    Hybrid state vector methods for structural dynamic and aeroelastic boundary value problems (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A computational technique is developed that is suitable for performing preliminary design aeroelastic and structural dynamic analyses of large aspect ratio lifting surfaces. The method proves to be quite general and can be adapted to solving various two point boundary value problems. The solution method, which is applicable to both fixed and rotating wing configurations, is based upon a formulation of the structural equilibrium equations in terms of a hybrid state vector containing generalized force and displacement variables. A mixed variational formulation is presented that conveniently yields a useful form for these state vector differential equations. Solutions to these equations are obtained by employing an integrating matrix method. The application of an integrating matrix provides a discretization of the differential equations that only requires solutions of standard linear matrix systems. It is demonstrated that matrix partitioning can be used to reduce the order of the required solutions. Results are presented for several example problems in structural dynamics and aeroelasticity to verify the technique and to demonstrate its use. These problems examine various types of loading and boundary conditions and include aeroelastic analyses of lifting surfaces constructed from anisotropic composite materials.
    Keywords: AERODYNAMICS
    Type: NASA-CR-3591 , NAS 1.26:3591
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  • 187
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    Axisymmetric and non-axisymmetric exhaust jet induced effects on a V/STOL vehicle design. Part 2: Analysis of results (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A wind tunnel investigation, employing a 1/8 scale model in an 11 foot transonic wind tunnel (Mach 0.4-1.4), was conducted to determine the jet effects of several exhaust nozzles on the aeropropulsive performance of a V/STOL fighter design. The force and pressure data show that significant differences in aeropropulsion performance can be expected by varying the exhaust nozzle type, jet area and deflection angle on an underwing nacelle installation. At unvectored conditions, the single expansion ramp nozzles show large performance gains relative to a circular nozzle installation. Additionally, a further drag reduction is realized when the nonaxisymmetric nozzle is vectored through a 10 degree deflection angle. The combined payoff of the vectored nonaxisymmetric nozzle over the baseline circular nozzle installation is equivalent to 25 percent of zero lift drag.
    Keywords: AERODYNAMICS
    Type: NASA-CR-166365 , NAS 1.26:166365
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  • 188
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    Axisymmetric and non-axisymmetric exhaust jet induced effects on a V/STOL vehicle design. Part 3: Experimental technique (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The jet induced effects of several exhaust nozzle configurations (axisymmetric, and vectoring/modulating varients) on the aeropropulsive performance of a twin engine V/STOL fighter design was determined. A 1/8 scale model was tested in an 11 ft transonic tunnel at static conditions and over a range of Mach Numbers from 0.4 to 1.4. The experimental aspects of the static and wind-on programs are discussed. Jet effects test techniques in general, fow through balance calibrations and tare force corrections, ASME nozzle thrust and mass flow calibrations, test problems and solutions are emphasized.
    Keywords: AERODYNAMICS
    Type: NASA-CR-166147 , NAS 1.26:166147
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  • 189
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    Aeroelastic analysis for helicopter rotors with blade appended pendulum vibration absorbers. Mathematical derivations and program user's manual (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Mathematical development is presented for the expanded capabilities of the United Technologies Research Center (UTRC) G400 Rotor Aeroelastic Analysis. This expanded analysis, G400PA, simulates the dynamics of teetered rotors, blade pendulum vibration absorbers and the higher harmonic excitations resulting from prescribed vibratory hub motions and higher harmonic blade pitch control. Formulations are also presented for calculating the rotor impedance matrix appropriate to these higher harmonic blade excitations. This impedance matrix and the associated vibratory hub loads are intended as the rotor blade characteristics elements for use in the Simplified Coupled Rotor/Fuselage Vibration Analysis (SIMVIB). Sections are included presenting updates to the development of the original G400 theory, and material appropriate to the user of the G400PA computer program. This material includes: (1) a general descriptionof the tructuring of the G400PA FORTRAN coding, (2) a detaild description of the required input data and other useful information for successfully running the program, and (3) a detailed description of the output results.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165896 , NAS 1.26:165896 , UTRC81-45
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  • 190
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    Flows over wings with leading-edge vortex separation (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The unsteady cross flow analogy reduces the steady three dimensional separation flow problem into an unsteady two dimensional flow problem in which the section shape changes with time. The two dimensional VORSEP code is extended to the case of arbitrary body growth rates in order to generate the initial vortex structures for the three dimensional free vortex sheet (FVS) code. Automatic procedures to reduce the wing geometry definition to a set of cross flow plane sections corresponding to the locations of the time step solutions and to generate the effective source distribution on each cross flow section to represent the section normal growth across the following steps are incorporated in the VORSEP code. Also, the wake shedding model is improved by adopting a redistribution scheme which improves the stability of the free sheet development with time. The improved wake shedding model combined with the redistribution scheme alleviated the numerical instabilities associated with the vortex rollup.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165858 , NAS 1.26:165858 , REPT-8105
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  • 191
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    Simulation of the fluctuating field of a forced jet (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The fluctuating field of a jet excited by transient mass injection is simulated numerically. The model is developed by expanding the state vector as a mean state plus a fluctuating state. Nonlinear terms are not neglected and the effect of nonlinearity is studied. The results show a significant spectral broadening in the flow field due to the nonlinearity. In addition, large scale structures are broken down into small scales. Previously announced in STAR as N82-34191
    Keywords: AERODYNAMICS
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  • 192
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    Study of highly sweptback wings by the free vortex sheet method (1982)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: The aerodynamic characteristics of highly sweptback wings with separations induced vortex flows have been numerically investigated using the free vortex sheet method, developed by Boeing Company, under a contract with NASA/Langley Research Center. The models studied included delta and straked wings, and wings with leading edge extensions. Also, PAN-AIR code has been used to design a fixed leading edge extension into a thick delta wing. The theoretical results predicted have been compared with the experimental data wherever available, and the code capabilities and limitations explored. New fuselage effects also have been considered in some cases.
    Keywords: AERODYNAMICS
    Type: NASA-CR-169559 , NAS 1.26:169559
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  • 193
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    Mean velocities and Reynolds stresses in a juncture flow (1982)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: Three mean velocity components and six Reynolds stresses were measured at two streamwise stations in a juncture flow using hot-wire anemometer techniques.
    Keywords: AERODYNAMICS
    Type: NASA-CR-168791 , NAS 1.26:168791
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  • 194
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    Aerodynamic performance of slender wings with separated flows (1982)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: The aerodynamic performance of low aspect ratio sweptback wings with vortex flows was numerically investigated using the free vortex sheet method. The models studied included flat, cambered, strake, and leading edge flapped wings of different planforms. The theoretical results predicted by the method were compared with the existing experimental data wherever available; and the code capabilities and limitations were explored. Also the effects of the wing thickness, fuselage, leading edge flap and multiple vortex modeling on the aerodynamic characteristics were studied.
    Keywords: AERODYNAMICS
    Type: NASA-CR-168768 , NAS 1.26:168768
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  • 195
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    An investigation of the aerodynamic characteristics of a new general aviation airfoil in flight (1982)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A low speed airfoil, the GA(W)-2, - a 13% thickness to chord ratio airfoil was evaluated. The wing of a Beech Sundowner was modified at by adding balsa ribs and covered with aluminum skin, to alter the existing airfoil shape to that of the GA(W)-2 airfoil. The aircraft was flown in a flight test program that gathered wing surface pressures and wake data from which the lift drag, and pitching moment of the airfoil could be determined. After the base line performance of the airfoil was measured, the drag due to surface irregularities such as steps, rivets and surface waviness was determined. The potential reduction of drag through the use of surface coatings such as KAPTON was also investigated.
    Keywords: AERODYNAMICS
    Type: NASA-CR-169477 , NAS 1.26:169477
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  • 196
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    A full potential inverse method based on a density linearization scheme for wing design (1982)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A mixed analysis inverse procedure based on the full potential equation in conservation form was developed to recontour a given base wing to produce density linearization scheme in applying the pressure boundary condition in terms of the velocity potential. The FL030 finite volume analysis code was modified to include the inverse option. The new surface shape information, associated with the modified pressure boundary condition, is calculated at a constant span station based on a mass flux integration. The inverse method is shown to recover the original shape when the analysis pressure is not altered. Inverse calculations for weakening of a strong shock system and for a laminar flow control (LFC) pressure distribution are presented. Two methods for a trailing edge closure model are proposed for further study.
    Keywords: AERODYNAMICS
    Type: NASA-CR-165991 , NAS 1.26:165991 , SC5277.21FR
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  • 197
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    Computational fluid dynamics of airfoils and wings (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: It is pointed out that transonic flow is one of the fields where computational fluid dynamics turns out to be most effective. Codes for the design and analysis of supercritical airfoils and wings have become standard tools of the aircraft industry. The present investigation is concerned with mathematical models and theorems which account for some of the progress that has been made. The most successful aerodynamics codes are those for the analysis of flow at off-design conditions where weak shock waves appear. A major breakthrough was achieved by Murman and Cole (1971), who conceived of a retarded difference scheme which incorporates artificial viscosity to capture shocks in the supersonic zone. This concept has been used to develop codes for the analysis of transonic flow past a swept wing. Attention is given to the trailing edge and the boundary layer, entropy inequalities and wave drag, shockless airfoils, and the inverse swept wing code.
    Keywords: AERODYNAMICS
    Type: Transonic, shock, and multidimensional flows: Advances in scientific computing; Proceedings of the Symposium; May 13, 1981 - May 15, 1981; Madison, WI
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  • 198
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    Comparison of laser anemometer measurements and theory in an annular turbine cascade with experimental accuracy determined by parameter estimation (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Previously announced in STAR as N82-28250
    Keywords: AERODYNAMICS
    Type: Engineering applications of laser velocimetry; Symposium; Nov 14, 1982 - Nov 19, 1982; Phoenix, AZ
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  • 199
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    Transient phenomena of shock-induced turbulent separation for a spikebody and stalling airfoil at transonic and supersonic speeds (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The time-dependent, compressible, Reynolds-averaged, full Navier-Stokes equations are applied to solve an axisymmetric flow around a forward-facing stepbody (spikebody) at supersonic speeds and a stalling airfoil at transonic speeds. Important transient and unsteady phenomena, not yet well understood, are examined, and significant new findings of the present solution to the phenomena are discussed. The phenomena described in detail are as follows: The evolution of the shock wave pressure built up by the impact of the pressure waves, one from the trailing edge; the separation of the flow as influenced by the shock wave; the location of the reversed flow, the separation point, and the reattachment point; and the transient (or unsteady) phenomena of the flow pulsation, oscillation, and stalling of the body and airfoil wake flow. The numerical results show that the transient flow instability is caused by a supersonic jet induced in the separation bubble by the shock-bifurcation (lambda shock) mechanism between the separation shock and the reflected shock. Pulsation and stall phenomena are caused by a sudden increase in the leading-edge pressure due to the jet and the separation bubble interacting along the stagnation point flow.
    Keywords: AERODYNAMICS
    Type: AIAA PAPER 82-1362 , Atmospheric Flight Mechanics Conference; Aug 09, 1982 - Aug 11, 1982; San Diego, CA
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  • 200
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    An initial look at the supersonic aerodynamics of twin-fuselage aircraft concepts (1982)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Results of two studies into the supersonic aerodynamics of twin-fuselage aircraft configurations are summarized. In the first study, a set of experimental data was obtained on a simple rectangular-wing twin-fuselage wind-tunnel model; this data was then used to evaluate prediction methods, assess favorable interference effects, and identify any unexpected or unpredictable aerodynamic phenomena. Results are presented which show that significant reductions in wave drag are possible through optimum body positioning and that existing aerodynamic prediction methods are adequate for making preliminary aerodynamic estimates. Several configuration concepts were theoretically explored in the second study, and results are presented which indicate the sensitivity of the twin-fuselage concept to various methods of integrating the aircraft components.
    Keywords: AERODYNAMICS
    Type: International Council of the Aeronautical Sciences; Aug 22, 1982 - Aug 27, 1982; Seattle, WA
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