Numerical Simulation of Sheetflow as Granular Material

Abstract

In the sheetflow regime, the concentration of the sediment is so high that particle/particle interaction plays an important role. In this study, a numerical simulation of the sediment transport in the sheetflow regime is performed on the basis of the Distinct Element Method (DEM) with a focus on particle/particle interaction. The characteristics of the vertical velocity profile of sediment particles in the sheetflow regime, which were reported in previous experiments, are reproduced well by the present simulation. Furthermore, the mechanism to determine the velocity profile of the sediment particles is clarified from the viewpoint of the granular material dynamics. Finally, the half-cycle averaged sediment transport rate under an action of sinusoidal oscillating flow is estimated from the result of the simulation under the quasi-steady assumption and is compared with the result of previous experiments.