A Combined Octree-advancing Front Method for Tetrahedra and Anisotropic Surface Meshes

A more automatic method for generation of tetrahedra and directional surface meshes are the two developments presented in this paper. Un-structured grids are generated for complex 3-D ge-ometries including multi-body domains. A combined octree-advancing front method is presented for the generation of the unstructured surface mesh as well as the tetrahedral volume mesh. The unique feature of this generator is that a special octree provides the local length scales of the mesh, which can vary signiicantly. This octree is automatically created and eliminates the need for a background mesh to determine the grid-spacing and stretching parameters. The grid generator is robust, geometry independent, and requires minimal user interaction. The technique is also presented for the generation of anisotropic surface meshes that result in a signiicant reduction in the number of triangular faces. Automatic local remeshing is also employed to improve quality of the tetrahedral mesh. The geometry independence of the octree-advancing front method is demonstrated through both surface and volume meshes generated around diierent complex 3-D conngurations. The robustness and exibility of the method is demonstrated through generation of both an all tetrahedral mesh and the tetrahedral part of hybrid prismatic/tetrahedral grids for vis-cous ows. The scalability of the generation time is shown through the generation of diierent meshes around the same geometry with varying levels of coarseness. The quality of the grid is evaluated via analytic test functions.