Study On Automatic Generation Of FDM Mesh Based On Body-fitted Coordinate

This paper focused on the study of grid generation based on body-fitted coordinate (BFC) system, which makes up for the deficiency of poor continuity and bad adaptability when simulating irregular regions under Cartesian rectangular coordinates with finite difference method.In the paper, the advantages and disadvantages of some common grids generation technology were discussed, and on this basis, the elliptic differential equation method was adopted for the two-dimensional BFC grid generation. The elliptic differential equation method was used for two-dimensional doubly and simply connected domains, the transform equation between the physical system and calculation system was solving in the inverse transformation, which was discretized using the central difference method. Appling the iteration method to solute the conversion equation, and then, the body-fitted coordinate grids were achieved. It is shown that this method can generate stable grid and is suitable to two-dimensional complicated section of any arbitrary shape.Based on the developed algorithm of grid generation, a 2-D BFC grid generation was developed. The feasibility of the program was verified under two-dimensional doubly and simply connected domains, respectively. The Drawing Exchange Files (DXF) analysis procedure was compiled, which may realize free reading under any graphics. After the optimization arrangement and discrete treatment, the boundary information of subdivision domain was obtained, which provides the precondition of BFC generate.To the grid generating procedure, friendly interface appeared, thus automatic grid generation realized under any subdivision portions. It is found that the generosity of the program is good enough to generate the grids for many complicated and curved-shape two-dimensional entities automatically. On the other hand, the BFC grids with fine grid distribution and good orthogonally can realize mesh refinement and sparse according to the curvature of the generation domains, which will possess vital significance in improving the border calculation accuracy and reducing the computation time obviously.