Numerical Simulations of Granular bed Erosion Under Martian Conditions

We present high-resolution Eulerian–Lagrangian simulations of sheared granular beds under Martian conditions. Erosion of the granular material on the surface of the Mars is important to understand the risks associated with plume-surface interactions (PSI) during spacecraft landing, in addition to understanding observed aeolian sediment transport. While much work has been done to characterize saltation and erosion, giving rise to phenomenological scaling laws, previous studies are almost entirely centered around the sub-aqueous regime (i.e. particle-to-fluid densityratios of O(1)) and in the incompressible limit. Unlike the more classically studied sub-aqueous sediment transport on Earth, Martian conditions exhibit density ratios of O(10⁵), and tangential flow induced by rocket plumes during landing events can reach supersonic speeds. In addition, recent experiments have found lower pressure environments yield a lower than expected saltation threshold. The present work focuses on erosion regimes under PSI-relevant Martian conditions with an emphasis on Mach number effects.