Study of Hybrid NS-DSMC Simulation Method with Chemical Non-equilibrium for Transitional Hypersonic Flow

An N-S/DSMC hybrid algorithm with chemical non-equilibrium is present by developing the MPC technique using current CFD and DSMC method based on same chemical reaction model. DSMC region is selected automatically according to CFD results in this hybrid scheme based on local Knudson numbers. A sub-relax technique is developed to deal with information exchange between CFD and DSMC to restrain the effect of statistical fluctuation from DSMC to CFD. This extends the application range of the DSMC and CFD method, and provides a way to predict the chemical nonequilibrium characteristics in near-continuum transitional flow regime. Hypersonic flow with chemical non-equilibrium around a 2D cylinder is simulated by the present N-S/DSMC hybrid method. Comparison shows that hybrid results are good agreement with full DSMC results in flow structure, non-equilibrium phenomenon, surface parameters and aerodynamics characteristics. This verifies the efficient adaptability and reliability of the present N-S/DSMC hybrid algorithm in simulating hypersonic flows for the transitional flow regime.