| In this paper, we try to simulate a bed-deformation using numerical computation. For calculation of sand particles, we employed Distinct Element Method called DEM. This scheme calculates the sand particle collisions by mechanical elements, such as springs, dashpots, and sliders. DEM enable us to calculate “multi-particle collision”. For flow calculation, the Unsteady Reynolds Averaged Navier Stokes model called URANS model was employed. In this model, we selected 2nd ordered non-liner k- model for turbulence scheme. To coupling between the particle calculation and flow calculation, we apply the two “two-way models”, which incorporate the particle-fluid interaction terms of the drag force with/without the shielding effect. In previous results1) with one-way model, they could not simulate accurate dune characteristics, such as sand wave movement, wave length, and wave height which depend closely on fluid conditions. In order to improve the accuracy, we developed a new scheme using two-way model. We conduct a numerical computation under existing hydraulic experimental conditions, and evaluate the advantages of two-way modeling on the bed-formations. |
