Dynamic mechanism of three-dimensional mixed-size grain/bed collision on non-flat bed using discrete element method

Abstract

The impact of particles on slope bed is not only one of the main processes of eolian saltation, but also lead to the sand surface damage and provide sufficient materials for the sediment supply process in desert rivers. In order to reveal the mechanism of excessive sediment supply in desert rivers, it is necessary to study the grain-bed impact process, which plays an important role on the wind erosion. In this study, based on the discrete element method (DEM) and previous researches, a three-dimensional numerical simulation is carried out to study the influence of the incident angle, incident angle, and lateral incident angle on grain-bed collision under different bed surfaces. Finally, by fitting the simulation data, we give the three-dimensional splash function of ejection velocity, ejection angle, and lateral ejection angle as well as lateral ejection velocity with the change of impact velocity, impact angle, and lateral impact angle on different bed surface. This study will enhance our understanding of the processes of eolian sand movement and will provide useful information about the mechanisms that drive sediment replenishment to desert rivers.