Semistructured mesh generation for three-dimensional Navier-Stokes calculations

Abstract

To mesh complex geometries efficiently, is the authors' view that a fully unstructured mesh generation technique holds the most promise. There are many papers detailing mesh generation and flow solutions for inviscid flows on unstructured meshes ; however, the computation of viscous flows on unstructured meshes is a relatively new area of research. To accurately and efficiently compute viscous flows, highly stretched cells aligned in the proper direction are required in the viscous layers. Many of the currently available unstructured mesh generators provide at most a limited ability to create these cells. In the current work a method that builds layers of highly stretched prismatic cells on an existing unstructured surface triangulation is described. The outer surface of this inflated triangulation provides a natural starting point for the advancing front algorithm used to fill the interior with tetrahedra. Care is taken to limit the possibility of a crossed-over mesh in concave geometrical regions. If the mesh does cross over, then the offending cells are removed. The combined algorithm of surface inflation and advancing front is demonstrated on a range of internal and external flow test cases. A limited number of flow solutions are also presented.