Structured Surface Definition and Grid Generation for Complex Aerospace Configurations

Extended Abstract l In the last decade Computational Fluid Dynamics has been extended to many different industrial areas. Numerical methods, parallel computation and visualization techniques for solving complex physics have been further developed in aerospace, automotive industry and hydraulic machinery. In order to increase efficiency and accuracy of a simulation, grid generation methods for complex geometries have become an important issue in CFD. The difficulty in producing high quality meshes in 3D within a short time has several reasons. First, producing a surface description is generally a time-consuming preprocess. Recently, for a reduction of this preprocessing time we focused on the direct CAD data conversion to an acceptable surface description for grid generators, such as multipatch surfaces. For this purpose, a filter is needed to reading CAD surfaces given in IGES format. This filter should be able to identify trimmed surfaces as well as surfaces with holes or overlaps and to ensure that a closed surface is generated. A recent experiment showed IGES readers of CITIA, ICEM, and Pro/Engineer to be incompatible. Therefore we wrote our own IGES reader based on an extended NASA IGES CFD standard. As an example we present the CAD data conversion from IGES into structured multipatches for the X-33 configuration provided by DASA, Munich, shown in Fig. 1. In the second stage, the multiblock topology