The simulation of sediment transport and erosion caused by free-surface flow based on two-phase SPH model with the improved Shields criterion

In this paper, a two-phase model based on the SPH method is established using the Newtonian fluid and non-Newtonian fluid to describe water and sediment respectively. In this model, the Oldroyd-B constitutive model and the modified Shields criterion by sediment thickness and sediment interface slope are used to predict sediment transport and erosion caused by free-surface flow. The drag force of the water flow on the sediment is also considered. In addition, a series of correction techniques, including the kernel gradient correction technique, density re-initialization, treatment of solid boundary, and velocity correction technique, has been used. The dynamic processes of sediment transport and erosion under three different scouring conditions are simulated and analyzed by the two-phase model. Compared with the simulated and/or experimental results from earlier studies, the results show that the two-phase SPH model can capture the principal phenomena of sediment transport and erosion caused by free-surface flow.