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At least 883 records · Page 49

Hypersonic gas dynamics of slender bodies

Hypersonic flow past slender bodies, discussing inviscid flows, outer edge singularity of boundary layer and three dimensional interaction on needle- like bodies

Cheng, H. K.↗

Calculation of inviscid surface streamlines and heat transfer on shuttle type configurations. Part 2: Description of computer program

A description of the computer program used for heating rate calculation for blunt bodies in hypersonic flow is given. The main program and each subprogram are described by defining the pertinent symbols involved and presenting a detailed flow diagram and complete computer program listing. Input and output parameters are discussed in detail. Listings are given for the computation of heating rates on (1) a blunted 15 deg half-angle cone at 20 deg incidence and Mach 10.6, (2) a blunted 70 deg slab delta wing at 10 deg incidence and Mach 8, and (3) the HL-10 lifting body at 20 deg incidence and Mach 10. In addition, the computer program output for two streamlines on the blunted 15 deg half-angle cone is listed. For Part 1, see N71-36186.

Dejarnette, F. R.↗

Hypersonic bodies of maximum drag for a given lift-to-drag ratio.

The problem considered in this paper is concerned with the aerodynamic design of the forebody shape of reentry vehicles in the blunt, homothetic, elliptic transversal contour, power-law longitudinal contour, raked-off configurational set. In particular, the forebody shape which maximizes the ratio of the forebody pressure drag to the free-stream dynamic pressure for a given lift-to-drag ratio and given geometric properties is determined. This problem is considered because recent survey articles indicate that its solution will provide useful qualitative design information about manned vehicles entering the earth's atmosphere from any of the foreseeable planetary missions. Single-integral equations relating the lift and drag in Newtonian hypersonic flow to the forebody geometry are derived and used to formulate the optimization problem which is solved by a direct numerical method.

Mcmillan, W., III↗

Cone transitional boundary-layer structure at Me = 14.

Experimental results suggest that the boundary-layer mean profiles in hypersonic flows may be highly transitional in the outer part of the boundary layer before the transition process is detected at the surface. Means of determining the initial location where the transition process begins in the outer part of the boundary layer are considered.

Fischer, M. C.↗

Inviscid surface streamlines and heat transfer on shuttle-type configurations.

A method is developed which calculates laminar, transitional, and turbulent heating rates on arbitrary blunt-nosed three-dimensional bodies at angle of attack in hypersonic flow. The geometry of the body may be specified analytically, or generated from a doubly cubic spline fit to coordinate points. Inviscid surface streamlines are calculated from Euler's equation using a prescribed pressure distribution. Laminar and turbulent heating rates are determined along a streamline by applying the axisymmetric analog to solutions of the axisymmetric boundary-layer equations. The location of the transition region may be specified optionally by geometric location, momentum thickness Reynolds number, or integrated unit Reynolds number along a streamline. Transitional heating rates are then calculated as a weighted average of the local laminar and turbulent values. Either ideal gas or equilibrium air properties may be used.

Dejarnette, F. R.↗

Analysis of thermal environment in the thrustor cavity of space vehicles

Wind tunnel tests to determine the mechanisms involved in producing the high local heating rates in and around the thrustor nozzle in a non-firing condition are reported. The geometry of a typical nozzle installation is described. Procedures for reducing the effects of hypersonic flow interactions in order to prevent excess local heating are explained.

Chiou, J. N.↗

Oblique shock-sound interaction at a freestream Mach number of about 20 in helium.

Detailed experimental measurements of the characteristics and level of pre- and postshock disturbances obtained for typical disturbance modes and shock angles are presented to aid in the evaluation of transition studies conducted in 'noisy' hypersonic wind tunnels. The presented data suggest that the shock is probably generating total temperature fluctuations in a fashion directly related to shock strength. Since in high supersonic and hypersonic flows the total temperature fluctuations are mainly contained in velocity fluctuations, it may be concluded that the predominant disturbances generated are vorticity as long as the postshock flow is at a sufficiently high Mach number.-

Weinstein, L. M.↗

Laminar boundary layer on a cone near a plane of symmetry.

The three-dimensional laminar boundary layer near the planes of symmetry of a cone with either outflow or inflow is studied in supersonic and hypersonic flow. Solutions are presented for a variety of values of three parameters, namely those of cross flow, external Mach number, and wall enthalpy ratio. Also asymptotic solutions for ranges of pertinent similarity variables are developed and used in numerical analyses so as to assure exponential behavior as the similarity variables approach infinity. Of special interest in the results is the existence for outflow, i.e., for the windward plane of symmetry, of a new solution branch and for inflow of four solution branches. The physical significance of the new solutions is discussed.

Wu, P.↗

Aerodynamic heating and loading within large open cavities in cone and cone-cylinder-flare models at Mach 6.7

The aerodynamic heating and loading distributions within large cavities exposed by surface openings to hypersonic flow were determined in the 8-foot high-temperature structures tunnel. Cone and cone-cylinder-flare models with cavities having regular and irregular surface-opening shapes were aerothermally tested at various angles of attack up to 30 deg. Tests were conducted at a Mach number of 6.7, a total temperature of 1800 K, a dynamic pressure of 80 kPa, and a stream unit Reynolds number of 6,000,000 per meter. The results showed that the heating rates at internal reattachment were generally lower but of the same order as the corresponding external heating rates; however, other internal heating rates were an order of magnitude lower. The internal flow showed characteristics of being funneled into jets or being dispersed dependent upon the internal surface contour.

Hunt, R. L.↗

Results of tests in the NASA/LARC 31-inch CFHT on an 0.010-scale model (32-OT) of the space shuttle configuration 3 to determine the RCS jet flowfield interaction effects on aerodynamic characteristics (IA60/OA105), volume 1

Tests were conducted in the NASA Langley Research Center 31-inch continuous Flow Hypersonic Wind Tunnel to determine RCS jet interaction effect on the hypersonic aerodynamic and stability and control characteristics prior to return to launch site (RTLS) abort separation. The model used was an 0.010-scale replica of the Space Shuttle Vehicle Configuration 3. Hypersonic stability data were obtained from tests at Mach 10.3 and dynamic pressure of 150 psf for the integrated Orbiter and external tank and the Orbiter alone. RCS modes of pitch, yaw, and roll at free flight dynamic pressure simulation of 7, 20, and 50 psf were investigated. The effects of speedbrake, bodyflap, elevon, and aileron deflections were also investigated.

Thornton, D. E.↗

Results of tests in the NASA/LaRC 31-inch CFHT on an 0.010-scale model (32-OT) of the space shuttle configuration 3 to determine the RCS jet flowfield interaction effects on aerodynamic characteristics (IA60/0A105), volume 2

Tests were conducted in the NASA Langley Research Center 31-inch continuous flow hypersonic wind tunnel from 14 February to 22 February 1974, to determine RCS jet interaction effect on the hypersonic aerodynamic and stability and control characteristics prior to RTLS abort separation. The model used was an 0.010-scale replica of the space shuttle vehicle configuration 3. Hypersonic stability data were obtained from tests at Mach 10.3 and dynamic pressure of 150 psf for the intergrated orbiter and external tank and the orbiter alone. RCS modes of pitch, yaw, and roll at free flight dynamic pressure simulation of 7, 20, and 50 psf were investigated. The effects of speedbrake, bodyflap, elevon, and aileron deflections were also investigated.

Thornton, D. E.↗

Results of tests in the NASA/LaRC 31-inch CFHT on an 0.010-scale model (32-OT) of the space shuttle configuration 3 to determine the RCS jet flowfield interaction effects on aerodynamic characteristics (IA60/0A105), volume 1

Tests were conducted in the 31-inch continuous Flow Hypersonic Wind Tunnel to determine RCS jet interaction effect on the hypersonic aerodynamic and stability and control characteristics prior to RTLS abort separation. The model used was an 0.010-scale replica of the Space Shuttle Vehicle Configuration 3. Hypersonic stability data were obtained from tests at Mach 10.3 and dynamic pressure of 150 psf for the integrated Orbiter and external tank and the Orbiter alone. RCS modes of pitch, yaw, and roll at free flight dynamic pressure simulation of 7, 20, and 50 psf were investigated. The effects of speedbrake, bodyflap, elevon, and airleron deflections were also investigated.

Thornton, D. E.↗

Aerodynamic heating on 3-D bodies including the effects of entropy-layer swallowing

A relatively simple method was developed previously (authors, 1973) for calculating laminar, transitional, and turbulent heating rates on three-dimensional bodies in hypersonic flows. This method was shown to yield reasonably accurate results for laminar heating on blunted circular and elliptical cones and an earlier version of the space shuttle vehicle. As the boundary layer along the surface grows, more and more of the inviscid-flow mass is entrained into the boundary layer, and the streamlines which passed through the nearly normal portion of the bow shock wave are 'swallowed' by the boundary layer. This phenomenon is often referred to as entropy-layer or streamline swallowing, and it can have a significant effect on the calculated heating rates. An approximate, yet simple, method for including the effects of entropy-layer swallowing in the heating-rate calculations is given.

Dejarnette, F. R.↗

Techniques for aerothermal tests of large, flightweight thermal protection panels in a Mach 7 wind tunnel

Recently developed experimental techniques permit evaluating thermal performance and structural integrity of full-scale panel concepts applicable to reentry and hypersonic vehicles in the Langley 8-foot high-performance structures tunnel. Rate and magnitude of surface heating and differential-pressure loading are independently controlled. Realistic temperature distributions are radiantly preheated into the panel prior to aerodynamic heating, and stream conditions are preselected to sustain the preheat surface heating input during aerodynamic exposure. During tunnel start and shutdown, panels are shielded outside the stream from potentially damaging transient acoustics and buffeting and are then rapidly inserted into the hypersonic flow. Infrared radiometry provides detailed surveys of surface temperatures.

Deveikis, W. D.↗

Results of test 0A82 in the NASA/LRC 31 inch CFHT on an 0.010-scale model (32-0) of the space shuttle configuration 3 to determine RCS jet flow field interaction and to investigate RT real gas effects

Tests were conducted in the NASA Langley Research Center 31-inch Continuous Flow Hypersonic Wind Tunnel to determine RCS jet interaction effects on hypersonic aerodynamic characteristics and to investigate RT (gas constant times temperature) scaling effects on the RCS similitude. The model was an 0.010-scale replica of the Space Shuttle Orbiter Configuration 3. Hypersonic aerodynamic data were obtained from tests at Mach 10.3 and dynamic pressures of 200, 150, 125, and 100 psf. The RCS modes of pitch, yaw, and roll at free flight dynamic pressure simulation of 20 psf were investigated.

Thornton, D. E.↗

Space shuttle orbiter trimmed center of gravity extension study. Volume 1: Effects of configuration modifications on the aerodynamic characteristics of the 140 A/B orbiter at Mach 10.3

Longitudinal and lateral-directional characteristics were obtained on several modified versions of the Rockwell International 140 A/B orbiter (0.010 scale). These modifications, designed to extend trim capability to center-of-gravity locations forward of the 65 percent fuselage station, consisted of two forebodies, two canard trimmers, and two body-wing fillets. Tests were performed over an angle-of-attack range of 12 to 36 degrees at a Reynolds number of 1.03 million based on body reference length. Data were obtained with the elevons and body flap deflected at the full-up and full-down design values. This investigation was conducted in the NASA Langley continuous flow hypersonic tunnel.

Bernot, P. T.↗

Unified nonlinear approach to both weak and strong-interaction problems

The numerical results are obtained for heat transfer, skin-friction, and viscous interaction induced pressure for a step-wise accelerated flat plate in hypersonic flow. In the unified approach here the results are presented for both weak and strong-interaction problems without employing any linearization scheme. With the help of the numerical method used in this work an accurate prediction of wall shear can be made for the problems with plate velocity changes of 1% or larger. The obtained results indicate that the transient contribution to the induced pressure for helium is greater than that for air.

Gupta, R. N.↗