Numerical simulation for coastal morphodynamics using DEM-MPS method

Numerical simulations were performed for morphodynamics with free water surface fluctuation using the DEMMPS method, which employs the discrete element method (DEM) and the enhanced moving particle semiimplicit (MPS) method for the solid and liquid phases, respectively. The reproducibility of the DEM-MPS method to a swash ripple formation process of a mixed grain bed is demonstrated. There, the bed is fully covered with water, and its void is filled with pore water. It is suggested that the ripple formation with coarsegrained particles activates the momentum exchange in the surface layer of the movable bed. In addition, a numerical simulation for a solitary wave induced by a landslide by DEM solid particles was carried out. Here, the applicability of the model in the situation where the pore water surface exists in a moving and deforming solidsediment layer is examined. The simulation results show that it is essential to apply the apparent volume to a fluid particle inside a solid-sediment layer to predict the water surface evolution accurately.

Automated summary

Numerical simulations were conducted for morphodynamics with free water surface fluctuation using the DEMMPS method, demonstrating the reproducibility of the process of swash ripple formation in a mixed grain bed. It was found that ripple formation with coarse-grained particles can activate momentum exchange in the surface layer of the movable bed.