Abstract
This paper presents the applicability of a numerical movable-bed channel as a prediction tool for dynamic interactions of flow and particle motions. Motions of flow and particles represented in the numerical movable-bed channel provided a good explanation for vertical distributions of particle velocity and concentration measured in a flume experiment on debris flow. We investigated effects of particle shapes and coefficients of contact forces (coefficients of restitutions and resistant friction angles) in the DEM method on simulated motions of flow and particles. Simulated motions of flows and spheres in the numerical movable-bed channel by using different coefficients of contact forces were not able to represent simulated motions of flow and gravel particles. We also studied forces exerted on flow and particles. Streamwise fluid forces on particles predicted negative values in upper parts and positive values in lower parts of the debris flow due to variation of magnitude of streamwise buoyancy and drag over the depth.
