Physical based numerical schemes for the discretization of the sediment settling term

In this paper, the discretization of the sediment settling term is investigated. Two potential problems induced by the incorrect discretization of this term are analyzed. It shows that even the first-order upwind algorithm, the most stable and conservative scheme, cannot always ensure stability and mass conservation. To tackle these issues, three rules are proposed. Based on these rules, two schemes are designed. The performances of different schemes are tested in a study of sediment motions under a wave-breaking situation. The results show that the unphysical problems are relieved or totally avoided by the new schemes.