LES-DEM coupled simulation of sediment particle saltating process in turbulent open channels

Sediment transport exists widely in natural water bodies. As one of the most important sediment transport modes, bed load transport has great influence on the scouring and deposition of the sediment near channel bed. Even though the saltation is the key process that affects the bed load transport, the detailed kinematics and dynamics of bed load particles in saltating process are still not fully understood. In this paper, a numerical model of sediment transport in open channel flows is built by combining Large Eddy Simulation (LES) with Discrete Element Model (DEM) using a fully four-way coupling method. Particular attention is paid to the characteristics of the kinematics and dynamics of the bed load particle in the saltating process. The model is validated with flow field and motion features of saltating process, and has good agreement with the experiments. The result shows that turbulence effect has great influence on the motion of saltating particles, the particle velocity and collision angles of the saltating particle have particular regularities of distribution. Compared with traditional one-way coupling method, the results also show great potential of the current LES-DEM model for the further research in sediment transport.