THE MATHEMATICAL MODEL OF RIVER BED SCOUR AND FILLDOWNSTREAM OF DONGJIANG HYDRO-PROJECT

摘要

On the base of the measurement on the prototype river channel, the laws ofrnsediment motion characteristics, and the mathematical model research, a numerical model isrndeveloped to simulate the river bed scour and fill downstream of Dongjiang Hydro-Project inrnconstruction. The basic equations of the mathematical model include 2-D shallow water flowrnequations, sediment transport equations, river bed evolution equation. For complex area, thernwhole region is divided into several sub-regions. In each sub-region, the Poisson equation isrnsolved to obtain the coordinates of nodes. The total mesh of numerical region is obtainedrnputting the mesh in each region together. The numerical method is the characteristic-based splitrnfinite element method (FEM). The model can simulate unsteady flows with non-linear river bedrnelevation and drying-wetting bed, transport of total sediment and bed evolution. Thernlongitudinal water surface, the cross-section velocity distribution, and the quatity andrndistribution of scour and deposit of the the numerical model are compared with the measuredrndata. The agreement between the computed and measued results is satisfactory.