Application of a Modular Particle-Continuum Method to Hypersonic Propulsive Deceleration

Abstract

A modular particle-continuum (MPC) method is used to quantify the e ect of continuum breakdown on aerodynamic predictions of Mach 12 hypersonic ow over a Mars entry aeroshell with a single-nozzle, sonic propulsive decelerator (PD). The MPC method loosely couples an existing direct simulation Monte Carlo (DSMC) code to a Navier-Stokes solver (CFD). Previous studies have shown that the MPC method can maintain the physical accuracy of DSMC in regions where the Navier-Stokes equations break down, while achieving the computational e ciency of CFD in regions that are considered fully continuum. Due to the very high number density within the jet core, application of the DSMC method across the entire ow eld is computationally expensive, and unnecessary. Comparison of predictions made by full CFD and the MPC method are performed at low and high thrust conditions. It is found that the jet induces an increase in the size of the rare ed region compared to the jet o con guration. Despite the additional mass added by the jet at high thrust, the degree of rarefaction is found to increase due to the intensi cation in ow gradients in the jet expansion region. In addition, it is found that the MPC results predict a larger recirculation region in the jet-shock layer interaction region compared to continuum predictions. The continuum aerodynamic drag coe cients are under predicted by 6% at low thrust con guration and over predicted by a factor of 2:7 at the high thrust condition. However, total axial force predictions made by continuum and hybrid methods are in very good agreement at both thrust conditions.