Development of parallel computational system for 3-D wind flow; around ground with structures using CAD/GIS data

本文建立了地面考虑结构的有限元模拟系统和三维风场的平行有限元模拟系统。在有限元建模系统中，采用通用数据格式（DXF）将CAD和GIS数据相结合，用于地面和结构的网格生成。为了准确地表达地理特征，三角形元素的一面既表达了等高线，又表达了山谷和山脉的线条。非结构化网格采用Delaunay三角剖分法，结构化网格采用多盒单元法。利用该系统，考虑到复杂的地基和结构形态，可以进行精确的有限元网格划分。在风的平行有限元系统中，采用基于Boussinesq近似的非定常Navier-Stokes方程作为风的控制方程，并采用了SUPG和PSPG。采用稳压法（稳压/Petrov-Galerkin）。采用P1/P1单元进行空间离散。在一个分布式内存并行集群上，进行了基于域分解和MPI的并行实现。将计算结果与实验结果进行了比较。结果表明，本文方法得到的数值结果与实验结果吻合较好。此外，从并行性能的结果中获得了良好的并行性能。

A finite element modeling system for ground considering structures and a parallel finite element system for 3-dimentional wind flow have been developed in this study.In the finite element modeling system, the CAD and GIS data were combined using common data format (DXF) and it was used for mesh generation for ground and structure. In order to express the geographical features accurately, a side of triangular element expressed not only the contour lines but also the valley and mountain lines. The Delaunay triangulation method was applied for making an unstructured mesh and the multi-boxcel method was applied for making a structured mesh. By using the present system, an accurate finite element mesh considering the complicated configuration of ground and structures.In the parallel finite element system for wind flow, the unsteady Navier-Stokes equation based on Boussinesq approximation was used for the governing equation of wind flow and the SUPG and PSPG.(pressure-stabilizing/Petrov-Galerkin) methods were used stabilization method. The P1/P1 element was employed for the discretization in space. Parallel implementation based on domain decomposition method and MPI was carried out on a distributed memory parallel cluster. The computed results were compared with the experimental results. From the results, the numerical result obtained by the present method is good in agreement with the experimental results. Furthermore, the good parallel performance was obtained from the results of parallel performance.