Thermal Non-Equilibrium Effects on the Flowfield Structure of Hypersonic Backward-Facing Step Flow

Abstract

An exploratory computational investigation was made on backward-facing steps in a rarefied hypersonic flow. The effect of the step back-face height on the thermal non-equilibrium was examined by employing the Direct Simulation Monte Carlo (DSMC) method. Results for the non-equilibrium between rotational temperature, vibrational temperature, “parallel” temperature, “normal” temperature, and translational temperature were presented and discussed at length. “Parallel” temperature and “normal” temperature are kinetic temperatures associated with x and y coordinate directions in the flowfield. Results showed that the flowfield is in thermal non-equilibrium in the boundary layer and in the shock-wave layer. In contrast, thermal equilibrium was verified at the vicinity of the step base. It was also found that entropy generation regions are related to the thermal non-equilibrium regions in the flowfield.