Numerical Simulation Study On Finite Method For Estuarine And Coastal Flow And Sediment Movements On The Unstructured Grids

With the development of high-capacity and high-performance computer technology, the mathematical model is adopted frequently, when it comes to hydrodynamic and sediment-transport study in estuaries and offshore. The research domain has expanded from one dimension to two dimension, even three dimension. For unstructured-grid Finite Volume Method(FVM) has clear physical meaning and can be used in complex computational domain, this method has been applied in the hydrodynamic and river dynamic computation in recent years. Based on the unstructured grid, the two-dimension hydrodynamic and sediment numerical model in the Cartesian coordinates is built in thesis.As to the sinuous coastal line and island in estuaries, using unstructured grid in the Cartesian coordinates to simulate the irregular boundary could not get high precision. Based on the Advancing Front technology with node spacing function which can control the changes of element size, a method for generating triangular grids on arbitrary planar domains is presented, and high precision can be got when simulating the irregular boundary.FVM in this thesis is based on Casulli[4](1992) semi-implicit mode. When the equation is discreted through adding dispersion correction, central scheme can be implemented on the gravity term and kinetic term. Respect to TVD high-convection format from Computer Aerodynamics, convection term is discreted by high-order scheme(two-order precision) , and the scheme can be used to control non-physics oscillation phenomenon of discontinues solution. The numerical model is programmed by Visual Fortran language.The two-dimensional hydrodynamic and sediment transport numerical model is proved and tested by the example of one dimension standing wave solution and the data of bed evolvement done by the former people, and hydrodynamics of Yangzi River is also simulated through this model. The results show that the flow and sediment movements are simulated successfully in this model, and the model is feasible in theory.