ICAS2002 CONGRESS NIQUES IN HYPERSONIC A H b r c h M t a o f h n s p a l

ypersonic viscous flows near simple-shape odies (wedge, cone, disk, plate, sphere, and otating cylinder) have been studied under the onditions of wind-tunnel experiments and ypersonic flights. The Direct Simulation onte-Carlo technique has been used to study he influence of similarity parameters on erodynamic coefficients in hypersonic streams f air, nitrogen, helium, and argon. It has been ound that, for conditions approaching the ypersonic stabilization limit, the Reynolds umber and temperature factor are primary imilarity parameters. The influence of other arameters (specific heat ratio, Mach number, nd viscosity parameter) becomes significant at ow Reynolds numbers (less than 10) and small alues of the hypersonic similarity parameter less than 1). The numerical results are in a ood agreement with experimental data, which ere obtained in a vacuum chamber at eynolds numbers from 0.1 to 200. The effect f nonequilibrium processes on simulation of hese flows over blunt bodies has been studied y solving the full Navier-Stokes equations and he viscous-shock-layer equations. The onequilibrium, equilibrium and “frozen ” flow egimes have been examined for various hysical and chemical processes in air and itrogen, including excitation of rotational egrees of molecular freedom, chemical eactions and ionization. It has been found that he binary similitude law is satisfied for blunt odies in the transition flow regime.