Research Of Two-Dimensional Hydrodynamic And Sediment Numerical Model With Colocated Grids

With the rapid development of the computer technology, the mathematical model is adopted more and more when it comes to the sediment study in the river. The research domain now has expanded from one-dimension research to two-dimension, even three-dimension research. The finite-volume solution method using colocated grids, which is a new and advanced numerical method, has been applicated in the hydrodynamic and river dynamic computation , that can be seen these years. On the basis of the wide research to the existing hydrodynamic and sediment transport numerical model, the transformation of the general curvilinear coordinates and the collocated grid system are brought into the two-dimensional hydrodynamic and sediment numerical model. Based on the collocated grid system, the two-dimensional hydrodynamic and sediment numerical model in the general curvilinear coordinates is built in this thesis.The research actuality, main numerical computational methods,the development trend and the major technique difficulty in the water-sediment mathematical model at home and abroad are generally introduced. The main job in the thesis is presented following above content.Aiming at the sinuous and irregular boundary in the natural river, the curvilinear grid in two dimension is generated adopted the technique of orthogonal body-fitted coordinate transform to adapt the regular calculating region to the irregular physical region. The governing equations of the model are transformed from the forms in the rectangular coordinate to the forms in the general curvilinear coordinate.During the governing equations'discretization,the physical variables are located in the collocated grid system. The SIMPLE algorithm with Carte-sian coordinates and non-orthogonal rectilinear coordinates using colocated grids, which is used to handle the problem of water level-velocity coupling,are described in detail. At the same time, measures to some key difficulties during the numerical simulation are put forward.The two-dimensional hydrodynamic and sediment transport numerical model in the general curvilinear coordinate, which is built in the thesis, is proved and tested through thesimulation calculation that is carried out on the expansion channel. The results show that the flow field and the evolution of river bed are simulated successfully in the model. And the model is feasible in theory.