Study Of Some Basic Problems Of Nonlinear Shallow Water Wave Model

The coastal structures are usually built in shallow water area, where the wave is highly non-linear, and the bathymetry is complicated. Thus it is difficult to simulate the propagation and deformation of the water waves. In this paper, some basic problems of nonlinear shallow water wave model are studied.The shallow water waves include dispersion waves and long waves. The moving boundary and wave breaking model for the Boussinesq model are studied. In this paper the recent development in Boussinesq model and wave breaking model are reviewed. In order to investigate the model and the numerical method further, 1D model based on Boussinesq equation is set up. The compact difference scheme is applied in Boussinesq equation. The slot method is used to treat the moving boundary, which is improved by choosing the premium parameters. Three wave breaking models for the Boussinesq model in this paper are built up. They are eddy viscosity-type model, roller model and turbulent model. The numerical results of wave runup and transmission in the slot are in good agreement with the analytical solutions and experimental data. In the equation which is adopted in this paper, eddy viscosity-type model is better than others. The results show that the models are proved to incorporate better dispersion, low numerical dissipation. Generation of waves using a source function method in computational areas is effective. The spongy layer for open boundary is good. And the moving boundary and wave breaking model are also satisfied.In the paper, 1-D, 2-D long wave equations are studied, the water quality model base on long wave eqution and advection-diffusion eqution is built up. The verification shows that the model is believable.By using the water quality model the impact on aquatic environment in the upstream, estuary and nearshore due to sluice built in Yongdingxin Estuary is simulated. The status of the upstream, estuary and nearshore aquatic environment before and after the sluice build are compared. Different frequence are simulated and analysed, and the suggestions are proposed to reduce the negative impact on the environment.