Fokker-Planck Simulations of the SHEFEX~II Vehicle

Abstract

The numerical prediction of aerodynamic and aerothermal loads is an essential part in the design and the optimisation of modern launch and re-entry vehicles. One of the goals of DLR is to be capable to predict the aerodynamic and aerothermal loads for the entire trajectory of these vehicles with high-fidelity simulation tools. The DLR in-house CFD solver TAU already provides very good capabilities for the prediction in the continuum region of flows. To extend our capabilities to the rarefied and transition regions we have started development on the kinetic Fokker-Planck (FP) method. We will do full 3D simulations of the SHEFEX II vehicle during decent at select trajectory points for altitudes between 70 km and 110 km with both FP and CFD. The mach number ranges from 9.2 to 9.5. We analyse and compare the flow fields of the simulations. We calculate the aerodynamic coefficients and the surface heat fluxes and compare them to the measured data from the flight experiment. We investigate the differences and provide a first estimate for the applicability and accuracy of our simulation methods in this flow regime.