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The effects of Reynolds number and turbulence on surface heat-transfer rates are numerically investigated for a 0.015 scale X-34 vehicle at wind tunnel conditions. Laminar heating rates, non-dimensionalized by Fay-Riddell stagnation heating, do not change appreciably with an order of magnitude variation in Reynolds number. Modeling a turbulent versus laminar boundary layer at the same Reynolds number increases the windside heating by a factor of four, portions on the leeside by a factor of two, and causes a 30 percent increase in wing leading edge heating. A discrepancy between laminar and turbulent heating trends on the windside centerline is explained by the presence of attached windside vortices in the laminar solutions, structures that are inhibited by the turbulence modeling. Wood, William A. Langley Research Center NASA/TM-1999-208998, NAS 1.15:208998, L-17794
The adaptation of ZONA unified hypersonic/supersonic method ZONA7U and its integration/development into a ZONA aerothermoelastic software system for transatmospheric vehicle (TAV)/thermal protection system (TPS) design/analysis was proven a successful tool through feasibility study with cases of a CKEM body, blunt cones, and a modeled X-34 wing body. Preceding the feasibility study, substantial effort was directed toward further development of a new code, ZSTREAM, and using it and ZABRO to replace the outdated modules in SHVD, thus to couple them with SHABP for aerothermoelastic applications. In the feasibility study, the cases are well validated with FD solutions. Next, computed heat rates by applying ZONA aerothermoelastic software to X-34 through two assigned hypersonic trajectories were shown and found to agree with those using MINIVER. A potential TPS design procedure was established using the obtained heat rates as an input to MINIVER, resulting in a minimum weight TPS per hot-wall consideration. With FEM/TRIM modules, ASTROS* yields the trim solution and stress distribution for a flexible X-34 at a typical trajectory joint, demonstrating the multifunctionality in MDO for the aerothermoelastic software.
Measurements and predictions of the X-33 turbulent aeroheating environment have been performed at Mach 6, perfect-gas air conditions. The purpose of this investigation was to compare measured turbulent aeroheating levels on smooth models, models with discrete trips, and models with arrays of bowed panels (which simulate bowed thermal protections system tiles) with each other and with predictions from two Navier-Stokes codes, LAURA and GASP. The wind tunnel testing was conducted at free stream Reynolds numbers based on length of 1.8 x 10(exp 6) to 6.1 x 10(exp 6) on 0.0132 scale X-33 models at a = 40-deg. Turbulent flow was produced by the discrete trips and by the bowed panels at ill but the lowest Reynolds number, but turbulent flow on the smooth model was produced only at the highest Reynolds number. Turbulent aeroheating levels on each of the three model types were measured using global phosphor thermography and were found to agree to within .he estimated uncertainty (plus or minus 15%) of the experiment. Computations were performed at the wind tunnel free stream conditions using both codes. Turbulent aeroheating levels predicted using the LAURA code were generally 5%-10% lower than those from GASP, although both sets of predictions fell within the experimental accuracy of the wind tunnel data.Hollis, Brian R. and Horvath, Thomas J. and Berry, Scott A.Langley Research CenterX-33 REUSABLE LAUNCH VEHICLE; AERODYNAMIC HEATING; HYPERSONIC SPEED; TURBULENT FLOW; SCALE MODELS; WIND TUNNEL TESTS; COMPUTATIONAL FLUID DYNAMICS; NAVIER-STOKES EQUATION; ALGORITHMS; BOUNDARY LAYER TRANSITION; REYNOLDS NUMBER; PANELS; THERMOGRAPHY; GLOBAL AIR SAMPLING PROGRAM; FREE FLOW
Aeroheating characteristics of the X-33 Rev-F configuration have been experimentally examined in the Langley 20-Inch Mach 6 Air Tunnel (Test 6770). Global surface heat transfer distributions, surface streamline patterns, and shock shapes were measured on a 0.013-scale model at Mach 6 in air. Parametric variations include angles-of-attack of 20-deg, 30-deg, and 40-deg; Reynolds numbers based on model length of 0.9 to 4.9 million; and body-flap deflections of 10-deg and 20-deg. The effects of discrete roughness elements on boundary layer transition, which included trip height, size, and location, both on and off the windward centerline, were investigated. This document is intended to serve as a quick release of preliminary data to the X-33 program; analysis is limited to observations of the experimental trends in order to expedite dissemination.Berry, Scott A. and Horvath, Thomas J. and Kowalkowski, Matthew K. and Liechty, Derek S.Langley Research CenterX-33 REUSABLE LAUNCH VEHICLE; AERODYNAMIC HEATING; AERODYNAMIC CONFIGURATIONS; WIND TUNNEL TESTS; HYPERSONIC SPEED; HEAT TRANSFER; BOUNDARY LAYER TRANSITION; AEROTHERMODYNAMICS; WIND TUNNEL MODELS; REYNOLDS NUMBER; FLAPPING; THERMOGRAPHY; SCALE MODELS; SPACECRAFT MODELS