Simulation of Moving Bed Erosion Based on the Weakly Compressible Smoothed Particle Hydrodynamics-Discrete Element Coupling Method

A complex interface exists between water flow and solid particles during hydraulic soil erosion.In this study, the particle discrete element method (DEM) has been used to simulate the hydraulic erosion of a granular soil under moving bed conditions and surrounding terrain changes.Moreover, the weakly compressible smoothed particle hydrodynamics (WCSPH) approach has been exploited to simulate the instability process of the free surface fluid and its propagation characteristics at the solid-liquid interface.The influence of a suspended medium on the water flow dynamics has been characterized using the mixed viscosity concept accounting for the solid-liquid mixed particle volume ratio.Numerical simulations of wall-jet scouring and reservoir sediment flushing on a mobile bed were performed and validated with experiments.The results show that the proposed WCSPH-DEM coupling model is highly suitable for determining parameters, such as the local maximum scour depth, the scour pit width, and the sand bed profile.The effects on the hydraulic erosion process of two important parameters of the mixed viscosity coefficient (initial solid volume concentration and initial viscosity coefficient) are also discussed to a certain extent in this study.