Nonequilibrium Velocity Distribution in Steady Regular Shock-Wave Reflection

Inspired by the outstanding contribution of professor Phillip Muntz in studying of molecular velocity distributions in shocks we examine numerically velocity distributions in the region of shock-shock interaction in the problem of the regular reflection of an oblique shock from the symmetry plane in a supersonic steady flow. Numerical results are based on di fferent mathematical models: the Navier-Stokes equations, the regularized 13-moment Grad equations (R13) and the Direct Simulation Monte Carlo (DSMC) method. A rather complicated flow structure is observed with a "non-Rankine-Hugoniot" wake behind the reflection point. The velocity distribution function is strongly non-equilibrium in the vicinity of the reflection point. The distribution also lacks the cylindrical symmetry typical of the distribution within a planar shock. The R13 equations are able to capture tiny features of the flow such as a wake downstream of the regular reflection. The Grad 13 velocity distributions also have a nonequilibrium form, but degree of non-equilibrium are much less pronounced than for the benchmark DSMC solution.