Investigation of Subsonic and Hypersonic Rarefied Gas Flow over a Backward Facing Step

Abstract

In the present study the Direct Simulation Monte Carlo (DSMC) method, which is one of the widely used numerical method to study the rarefied gas flows, is applied to investigate the flow characteristics of a hypersonic and subsonic flow over a backward-facing step. The work is driven by the interest in exploring the effects of the Mach number on the rarefied flow behaviour. The primary objective of this paper is to study the variation of velocity, pressure and temperature with Mach number. The numerical tool is validated with well established results from the literature and a good agreement is found among them. The computational results indicate that the flow downstream of the step is effected by the strong expansion near the step. The compressiblity and rarefaction effects also influence the velocity and temperature distributions in the hydrodynamic and thermal boundary layers.