Direct Simulation Monte Carlo of Counter Flow Jet Interaction with Reentry Capsule Rarefied Flow

In this study, DSMC simulation of rarefied hypersonic flow over re-entry vehicle with and without counter flow jet is presented using the modified DsmcFoam solver. DsmcFoam modification includes implementation of VSS collision model for more accurate collision model, Non-uniform initial condition adjustment for faster convergence, Local Knudsen number post-processing for using the adaptive grid generation, and non-uniform boundary condition adjustment with different gas species for multi-gas flow interaction simulations. Also, effect of counter flow jet on the vehicle aerodynamics and aerothermodynamics is investigated. New validation test cases from VKF tunnel data of Apollo and blunt-cone re-entry geometries are compared to DsmcFoam which the results are in suitable agreement with experimental data and also MONACO code results. Then, rarefied hypersonic flow over Apollo re-entry vehicle with a counter flow jet is simulated and the effect of counter flow jet on the vehicle aerodynamics and aerothermodynamics is investigated. The major effect of counter flow jet is the changing the bow shock configuration and its distance from the vehicle. Consequently, it is observed that by increasing counter flow jet velocity or density, the reduction of the drag coefficient and heat flux on the vehicle will occur. Also, the variation of the velocity or density of counter flow jet leads to different jet-flow interaction patterns which are studied.