Numerical simulations of rarefied reentry flows

A review of recent calculations obtained with Bird's direct simulation Monte Carlo (DSMC) method is presented for the transitional flowfield encountered at reentry conditions. Consequently, the emphasis is the real-gas effects resulting from a highly energetic nonequilibrium flow. The DSMC calculations for both wide-angle and slender bodies are compared with continuum calculations. The wide-angle body calculations simulate the windward nose of the Shuttle Orbiter and projected aeroassisted orbital transfer vehicles. For the slender, blunted configurations, both two-dimensional and axisymmetric results are presented. Comparisons between the DSMC and continuum calculations show the altitude range where differences in flowfield structure and surface quantities become significant.