High-fidelity modeling and numerical simulation of cratering induced by the interaction of a supersonic jet with a granular bed of solid particles

摘要

AbstractThe dynamics of cratering caused by a supersonic jet on a granular bed of solid particles is investigated using a high fidelity, two-phase model and numerical simulations. To model the gas phase, the Large Eddy Simulation (LES) approach is used and a kinetic theory based model is employed for the solid phase. Three-dimensional time-dependent simulations are conducted for the purpose of elucidating the morphological features of the crater and their evolution with time. Parametric variations of the initial conditions are performed to understand the effect of the initial solid volume fraction in the bed, of the coefficient of restitution, of the jet Mach number, of the particle diameter, and of the particle material density. Simulation snapshots of the craters are in qualitative agreement with images from the Mars Science Laboratory (MSL) mission and from Earth-based experiments. Analysis of the results shows that solid particle compaction at the crater base and side walls increases with increasing volume fraction of the undisturbed particle bed and reaches solid volume fractions close to 0.65. The coefficient of restitution is shown to have no effect on the large scale dynamics of the crater but affects the small scale features, particularly the shape of elongated bursts of solid particle clouds as well as radially aligned structures on the outer crater walls. A smaller jet Mach number results in a smaller crater characterized by ridge-like structures and walls at an angle of approximately 45° with respect to the undisturbed bed whereas larger Mach number jets create craters with walls approximately perpendicular to the undisturbed bed. A smaller particle size and a lighte