3D simulations of sediment transport in Yellow Sea

Abstract

We report in this talk a recent progress in developing a modeling system of predicting three-dimensional transport of sediments coupled with multiple-scale circulation, wave and suspended sediment modules, keeping in mind the application to coastal sea regions with non-uniform distribution of suspended and bed sediments of both cohesive and non-cohesive types. The dependence of distribution coefficients is inversely proportional to the sediment particle size. The hydrodynamic numerical model SELFE that solves equations for the multiple-scale circulation, the wave action and sand transport on the unstructured grids has been used as a base model. We have extended the non-cohesive sediment module of SELFE to the form applicable to mixture of cohesive and non-cohesive sedimentary regimes by implementing an extended form of erosional rate and a flocculation model for the determination of settling velocity of cohesive flocs. The exchange of sediment between the bed and the flow is modeled using sink and source terms acting on the bottom computational cell. These terms represent the processes of sediment entering the flow due to erosion flux and the sediment settling down due to the depositional flux. Total flux,the difference between erosion and deposition fluxes, need to be defined for the each sediment size class. For the mixture of cohesive and non-cohesive sediments we follow the assumptions based on the parameter of c coastal sea regions with non-uniform distribution of suspended and bed sediments of both cohesive and non-cohesive types. The dependence of distribution coefficients is inversely proportional to the sediment particle size. The hydrodynamic numerical model SELFE that solves equations for the multiple-scale circulation, the wave action and sand transport on the unstructured grids has been used as a base model. We have extended the non-cohesive sediment module of SELFE to the form applicable to mixture of cohesive and non-cohesive sedimentary regimes by implementing an extended form of erosional rate and a flocculation model for the determination of settling velocity of cohesive flocs. The exchange of sediment between the bed and the flow is modeled using sink and source terms acting on the bottom computational cell. These terms represent the processes of sediment entering the flow due to erosion flux and the sediment settling down due to the depositional flux. Total flux,the difference between erosion and deposition fluxes, need to be defined for the each sediment size class. For the mixture of cohesive and non-cohesive sediments we follow the assumptions based on the parameter of c