Multigrid Acceleration in a 3D Navier-Stokes Solver Using Unstructured Hexahedral Meshes with Adaptation

A 3D Navier-Stokes solver for unstructured meshes is presented. The originality of the approach lies in the use of hexahedral meshes, that, in contrast with tetrahedral grids, ensure a good quality mesh in boundary layers, without having to resort to hybrid grid techniques. These meshes are adapted during the computation: relying on the detection of flow phenomena, cells can be either anisotropically refined or removed following a full hierarchical approach. The present solver uses a cell-centered formulation and a new approach is used for the multigrid strategy, showing promising results on some Navier-Stokes test cases.