Testing Continuum and Non-Continuum Descriptions in High Speed Flows

Abstract. Detailed simulations were performed with a continuum-based Navier-Stokes, a gas kinetic Bhatnagar-Gross-Krook (BGK) and the Direct Simulation Monte Carlo (DSMC) flow solvers to identify and characterize the translational and internal energy mode relaxation in high speed flows. Argon and nitrogen shock structures were simulated to quantify the nonequilibrium state. A new multi-translational temperature gas kinetic model was developed to match the capability of DSMC. Bulk viscosity as an adjustable parameter to recover small departures from rotational equilibrium in the Navier-Stokes equations is explored in weak shock structures. In the context of nitrogen dissociation, the models of vibrational bias for the dissociation kinetics are presented