個別要素法を用いた河床変動計算

Abstract

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-e model for turbulence scheme. To coupling between the particle calculation and flow calculation, we apply the relationship between the saltation layer and the Shields stress which proposed by M. Colombini and A. Stocchino. In our previous results, we cannot simulate dune characteristic, such as sand wave movement, wave length, and wave height which correspond particular fluid condition. From this point, this paper proposes a new scheme which evaluate saltation layer with Shields layer. We conduct a numerical computation follow a well-studied fluid condition, and evaluate its effect on the bed-formations.