Gas-Granular Computational Fluid Dynamics Simulation of Rocket Plume Impingement On Close-Range Surfaces in Near Vacuum

Plume surface interaction (PSI) modeling has become important in the design of large landing vehicles. Loci/GGFS has been used to predict crater formation in near-vacuum environments. Quantitative and qualitative validation of crater and pressure predictions are made herein with Loci/GGFS. The validation uses experimental data from hot fire tests performed by Clark in 1970. Simulations were conducted with two different soil models, an irregular monodisperse sand model and a spherical monodisperse sand model. For soil test base pressure measurements, the experimental sensors were out of range, but predictions match within a factor of 2. Agreement of the base pressure profile through time implies that the crater shape agrees through time. Gas only pressure predictions were also made and compared to the experiment. Gas only dished surface pressures were within 20% and the base pressures were within 75%. Loci/GGFS predicted a soil volume eroded which agrees well with the experiment.