Numerical simulation of sediment erosion and transport using consistent particle method

Abstract

This paper presents an extension of the Consistent Particle Method (CPM) to simulate the erosion and transport of non-cohesive sediments by adopting an incipient motion approach and proposing new ways of modelling erosion. Sediment particles comprising water and sand grains are initially treated as fixed before erosion and transition to a fluid upon erosion and subsequent transport by water flow. The proposed erosion model permits erosion of sediment particles in all bed sublayers within a single time step, while eroded sediment particles can redeposit and become un-eroded again. For scenarios where numerical particle size is much larger than sand grain size (e.g., fine sand erosion), the erosion status of a sediment particle is determined by a criterion involving a net loss of half of the sand grains within the particle. This approach overcomes the large disparity between numerical and experimental erosion rates as reported in some studies of particle methods. In simulating the transportation of eroded sediment particles, CPM uses the physical properties of sediment without using artificial parameters such as artificial viscosity. The CPM results are validated through four examples involving coarse and fine sand grains, which are dam break on an erodible bed, sediment scour from a wall jet, scour behind a seawall, and continuous overflow-induced sediment flushing.