A Cell Center Finite Volume Model for 2D Numerical Simulation of Deposition-Erosion and Transport of Suspended Sediment in Free Surface Flows

摘要

The details of a cell center finite volume depth-integrated free surface flow solver which solves two-dimensional advection and diffusion equation of suspended sediment in a coupled manner. The set of flow equations is shallow water equation which considers the effect of the bed topography variations. The algorithm includes a parabolic algebraic eddy viscosity model for simulation of turbulent effects. The depth integrated equation mathematically describes the variation of the sediment concentration due to the deposition-erosion phenomenon via its sink-source terms. In present algorithm, various coefficients for non-equilibrium adaptation length in the source-sink terms of clear water sediment transport formulation is tested and verified. A cell center finite volume formulation for unstructured triangular meshes is utilized with explicit time integration. In order to prevent numerical instabilities, proper artificial viscosity terms are added to the formulation, without degradation of accuracy. Validation of the suspended sediment module is accomplished through simulation of two test cases in straight channels. The first test case, presents the net sediment entrainment into the clear water from channel bed with zero sediment deposition. The second one describes the sediment deposition on the perforated channel bed with zero sediment entrainment.