Numerical Simulation For Coupling One-dimensional River And Two-dimensional Dike-break Waves

The fast-spreading dike-break waves caused by river dike-burst can do great harm to the safe and properties of human being. Therefore, the coupled numerical simulation of river and dike-break waves is of great importance to the prediction of submerging process in polder. A hydraulic model of coupling 1-D river dike-breaking and 2-D dike-break waves is established in the paper. The Saint-Venant equations used in the simulation of river are discretized by the Preissmann implicit scheme, which shows good stability and high precision. The calculation is coupled with the numerical simulation of the breach. The dyke-break process is supposed to be gradual and the breach is simulated as an echelon growing wider with time. The TVD-MUSCL scheme based on FVM (Finite Volume Method) and unstructured grids is used to the computation of dike-break waves. The results show that this scheme is not only nonoscillatory, but also capable of treating hydraulic jump automatically. The hydraulic model of coupling 1-D river and 2-D dike-break waves realizes the transition from 1-D calculation water area to 2-D water area, and it shows the process of river dyke-breaking, the velocity variation of the breach flow and the flow characteristic of diffraction, reflection and deformation during the propagation of dike-break waves. The simulation can realistically show the burst process of dike. It is concluded that the model can predict the submerge process and area effectively, and it provides academic base for establishment of flood forecast system.