2-D numerical modeling unsteady flow and sediment transport in Chongqing Reach of the Yangtze River

A 2-D numerical model for simulating unsteady flow and sediment transport in Chongqing Reach of the Yangtze River is developed considering its channel characteristics. Based on recent research findings in dynamics of silt sediment, the non-equilibrium sediment transport theory, as well as the formulae of sediment carrying capacity which can reflect the features of suspend and bed-load transport in Chongqing Reach, are adopted in the model. The finite element method is employed to deduce the discretized equations of the model due to the irregular geometrical boundaries at river confluences. Firstly, calculating area is divided into triangle meshes. Then, the integral forms of equations given below are deduced by Galerkin weighted-margin method. Method of Mass Concentration is used to simple the matrix coefficient, and the Adams 2-order Predictor-Corrector is used to solve the dispersed finite element equations. Computational results demonstrate that the model can effectively simulate the water and sediment transport, scouring and silting of the riverbed in Chongqing Reach.