| Research Abstract |
The research is for the proposal of the mesh generation method of 3-dimensional finite element model of the orographic wind flow surrounding civil engineering structures like bridge and buildings using parallel computer, and following results are obtained: (1) The anlysis has to treat natural and artificial shapes, I.e, ground surface and buildings. The shape is created in computer by the triangulation of polygon obtained from TIN and CAD and their intersection in a same space. (2) The volume triangulation is then achieved for the 3-dirnonsional space surrounded by the triangles and the volume is replaced by a set of tetrahedral. (3) Final stage of the modeling is the mesh refinement of the set of tetrahedral, and this procedure consists of two stages; topological and geormetric improvement. The former changer the number of nodes and elements, and the latter only the position of nodes. For the modifiation of topology new tool was developed by using the Delaunay triangulation, and the modification of geometry is achieved by the Laplacian method, which relocates nodes to appropriate portion.
The method proposed in this reseach work is based on 3-dimensional Delaunay triangulation, which accepts only the location of nodes, and, therefore, proposed method can create required finite element model when nodes are prepared on the surface of analysis domain. As far as real numbers like nodal coordinates are treated, nuumerical error may affect the final result, and improved Delaunay triangulation method is proposed in order to avoid the increase of numerical error through the triangulation.
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