BLUNT-BODY RAREFIED WAKES FOR EARTH ENTRY

Direct simulation Monte Carlo (DSMC) and Navier-Stokes axisymmetric ca lculations are presented for hypersonic low-density flow about a 70-de g blunt cone afterbody configuration, The flow conditions simulated ar e those experienced by a space vehicle for an altitude range of 105-75 km during Earth entry. The entry velocity considered is 7 km/s. A ste ady vortex is predicted in the near wake for 75 and 85 km altitudes by both calculations, The flow remains attached for 95 and 105 km altitu des, Comparisons of DSMC and Navier-Stokes calculations for the wake f lowfield become less and less favorable with increasing altitude. Comp arisons of surface quantities shaw reasonable agreement between DSMC a nd Navier-Stokes calculations along the forebody. However, the surface quantities along the afterbody calculated from DSMC and Navier-Stokes calculations differ significantly at the higher altitudes.