Study on unstructured mesh generation technique based on quad-tree method

The arithmetic of quad-tree mesh generation was studied in order to solve the problem of the finite element automatic quadrilateral mesh generation for a two dimensional complex region. The data structure and recursion generation of quad-tree mesh was described, and the method of black-white property judgment of mesh based on computer graphics was presented. Two modified methods of boundary-mesh were given and compared. The operation of mesh such as ordering, finding and inserting was carried out according to the character of quad-tree data structure and the neighbor-finding of mesh was realized by using the algorithms of the last common ancestor. The results show that the method based on the quad-tree was very useful for the finite element automatic quadrilateral mesh generation in two dimensional regions, which only depends on the geometrical character of the region and has great flexibility for complex boundary. The meshes generated in planar were all quadrangular and only a few triangular near the boundary. In addition, the operation of meshes such as generating, ordering and finding was efficient and timesaving.