The fidelity of DSMC method to analyze the aerothermodynamics of the pure continuum flow regime

Abstract

Abstract The statistical probabilistic Direct Simulation Monte Carlo (DSMC) method was developed to interrogate the flow regime, in which thermal non-equilibrium exists and flow properties are non-continuous. Unfortunately, the DSMC method had not been preferred for the pure continuum flow regime ascribed to the computational burden arises with the computation of a large number of simulated molecule trajectories. However, this study showed that the DSMC method can handle the number density of real molecules of the pure continuum flow regime. The DSMC predictions were in close proximity to the experimental measurements taken on an Orion aeroshell model at Mach 11.4, 12.4, and 12.5 of reacting air in an expansion tunnel facility. The measurements corresponded to laminar boundary layer conditions, whereby Schlieren images were taken to assess the shockwave encapsulating the Orion aeroshell. The DSMC model predicted no isolated bump of the stagnation point heat flux, which was in line with the experiments. At a 20° angle of attack of the aeroshell, the model could capture the non-axisymmetric flow-field, in which the shear layer was attached at the windward side aftbody and detached at the leeward side aftbody. Thinning of the shockwave with the increase of flow-field temperature and molecular dissociation was also visibly distinct. The outcomes suggest the fidelity of the DSMC method in capturing the molecular interactions and the associated reaction kinetics in regimes varying from continuum to a rarefied gas without any substantial compromise of accuracy.