The Finite Element Mesh Generation And Wave Field Simulation

Mesh generation is an essential precondition for the numerical approximate solution when finite element method, finite difference method and finite volume method are applied to solve partial differential equations. It is difficult to input boundary conditions and generate sound mesh when large size and or geometrically complicated domains are confronted.On a certain extent those questions prevent applying finite element method on studies of large size field .In view of this situation, a few mesh generation methods are proposed and developed in this thesis.First of all, how to input exact and convenient boundary condition is the problem to be solved in our field. Mapinfo software are applied to input boundary conditions which reduces much data input task.Convenient topography input makes data input exact and reduce much error and task that brought by manual input. It also improves on boundary input method in our field.Secondly, mesh generation of the domain is the first step to simulate wave field by numerical method. An automatic quadrilateral mesh technique for arbitrarily shaped planar regions with minimal user expertise and minimal interaction is proposed in this paper. The method is base upon the advancing front technique which constructs unstructured mesh of the domain of interest from its boundary.Approaches such as smoothing,seaming and topological refinement are incorporated in the generator in order to improve the quality of the meshes.Thirdly, method of mesh generation is improved daily. Efficient mesh generator Gridgen is applied to generate all kinds of structured and unstructured meshes in order to explore more mesh methods and make a compare. Not only many high quality meshs are constructed but also those meshs are applied in actual numerical simulation and computation.Finally, the contents of offshore mathematical wave model is very plenty and applied abroadly. Mildslope and some improved equations have mighty function.They can solve many coastal and offshore engineering problems which include mild slope and steep slope, deep water and shallow water, linearity and none linearity, regular wave and irregular wave, large size water area and dock basin , navigation channel and breakwater etc. FEM schemes is adopted in solve hyperbolic mildslope equation in this paper in order to simulate large wave field because it can deal with complex boundaries in coastal numerical simulations. A great deal of examples and comparatives prove that the whole proposed method can solve practice problem very well. So it can be applied in wave field computation of actual port numerical simulation.