Sediment Transport in Shallow Waters as a Multiphysics Approach

Abstract

AbstractSuspended particle and bed-load transport are usually high during flooding events. For that reason, sediment transport is an important feature to be taken into account when studying floods. Measures that aim to mitigate the negative impacts of floods depend on such studies. Sediment transport phenomena are complex due to their coupling behavior with fluid flow. Due to the erosion and sedimentation of particulate matter, the ground surface changes during the passing of a flood. The courses of unregulated rivers and wadis after floods are different than those before floods. Flowing water transports sediments, and vice versa; sediment redistribution affects the flow of water due to changes in the ground surface and other factors. Computer simulations of sediment transport must take the coupling between water flow and transport processes into account. Here, a multiphysics approach in such a coupled model is presented. Shallow water equations (SWE) representing water height and velocity are coupled with equations for suspended particulate matter and bed loads. Using COMSOL Multiphysics software, an implementation is presented that demonstrates the capability and feasibility of the proposed approach. The approach is applied to the problems of scouring and sedimentation at obstacles, which are particularly important for ensuring the stability of bridges across rivers and wadis.