ZONALLY DECOUPLED DIRECT SIMULATION MONTE-CARLO SOLUTIONS OF HYPERSONIC BLUNT-BODY WAKE FLOWS

Direct simulation Monte Carlo (DSMC) solutions are presented for the h ypersonic now behind a blunt body in which the wake region is solved i n a zonally decoupled manner. The forebody now is solved separately us ing either a DSMC or a Navier-Stokes method, and the forebody exit-pla ne solution is specified as the inflow condition to the decoupled DSMC solution of the wake region. Results are presented for a 70-deg, blun ted cone at now conditions that can be accommodated in existing low-de nsity wind tunnels with the Knudsen number (based on the base diameter ) ranging from 0.03 to 0.001. The zonally decoupled solutions show goo d agreement with fully coupled DSMC solutions of the wake flow densiti es and velocities. The wake closure predicted by the zonally decoupled solutions is in better agreement with fully coupled results than that predicted by a fully coupled Navier-Stokes method, indicating the nee d to account for rarefaction in the wake for the cases considered. The combined use of Navier-Stokes for the forebody with a decoupled DSMC solution for the wake provides an efficient method for solving transit ional blunt-body flows where the forebody now is continuum and the wak e is rarefied.