Numerical simulations of an underexpand jet impinging on a granular bed

The interactions between rocket exhaust plumes and the surface of extraterrestrial bodies during spacecraft landings involve complex multiphase flow dynamics that pose significant risk to space exploration missions. The two-phase flow associated with plume-surface interactions (PSI) is characterized by high Reynolds number transonic conditions with particle concentrations ranging from dilute to close-packing. In this talk, an Eulerian-Lagrangian framework for simulating gas-solid compressible flows under conditions relevant to PSI is presented. Simulations of underexpanded jets impinging on granular surfaces are performed to elucidate the role of nozzle pressure ratio on crater morphology, and quantify two-phase statistics during the erosion process.