NUMERICAL-SIMULATION OF SHEETFLOW AS GRANULAR MATERIAL

In the sheetflow regime, the concentration of the sediment is so high that particle/particle interaction plays an important role. In this st udy, 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 we ll by the present simulation. Furthermore, the mechanism to determine the velocity profile of the sediment particles is clarified from the v iewpoint of the granular material dynamics. Finally, the half-cycle av eraged sediment transport rate under an action of sinusoidal oscillati ng how is estimated from the result of the simulation under the quasi- steady assumption and is compared with the result of previous experime nts.