Unstructured Grid Generation and Flow Adaptation for External Aerodynamic Flows

Abstract

Abstract The generation of high-quality computational grids for complex aerodynamic configurations remains an important area of concern, hindering the routine application of Computational Fluid Dynamics (CFD). The block-structured approach has proved to be highly successful, but it does in general require extensive user intervention and expertise. Alternatively, unstructured grids can be made to fit very complex geometries in a relatively straightforward manner and has been shown to be highly effective for grid adaptivity[4]. Therefore, much progress has been made over the past few years to develop fast and robust unstructured grid generators. Two well-known approaches commonly used for construction of triangular unstructured grids are the Delaunay criterion and the advancing front method. The Delaunay triangulation, although it has many interesting properties [7] does not address the issues of grid point creation and boundary conformity. Additionally this method is not naturally capable of generating high aspect ratio cells required for viscous flow calculations. The advancing front method has received much attention, particularly because of its self-sufficiency and grid quality ([1],[4]). However, special care must be taken when choosing the data structure to efficiently perform the relevant searches.