Discrete particle simulation of jet-induced cratering of a granular bed

Jet-induced catering in a granular bed is an interesting phenomenon observed in nature and in many industries. This paper presents a numerical study of this process by the combined approach of computational fluid dynamics (CFD) for gas phase and discrete element method (DEM) for solid phase. The applicability of the model is verified by comparing the numerical results with experimental measurements of crater depth and crater shape in the cratering regime of Diffusion Driven Flow. The sensitivity of numerical results to model parameters such as restitution coefficient, sliding friction coefficient and Young's modulus is also examined. Then, the effect of jet velocity is quantified, followed by a detailed analysis of flow characteristics and forces between particles, as well as between particles and fluid, to understand the underlying mechanisms. Based on the simulated results, two equations are respectively formulated to estimate the asymptotic crater depth and crater width.