Generation of Exascale Meshes by Subdivision of Coarse Meshes

The CFD Vision 2030 document predicts a need for unstructured meshes that are two orders of magnitude larger than can currently be generated. This paper describes a new approach to create extremely large meshes (more than 100 billion cells) from meshes of relatively modest size (a few million or tens of millions of cells). This approach subdivides all edges into N segments, faces into N^{2} faces, and cells into N^{3} cells. New cells descended from a common base cell can be created without need for ordinary meshing primitives, making this approach extremely fast and robust. Also, mesh subdivision can be applied to partitioned meshes, eliminating the massive memory requirements that would otherwise restrict output mesh sizes. Examples as given for straight and curved meshes, both tetrahedral and mixed element. The largest output mesh created has 347 billion cells, and was created using a single core on a laptop in about eight hours. The software implementing this approach is available under the GNU Lesser General Public License.