Anisotropic solution-adaptive for turbulent viscous Cartesian grid method flow simulation

An anisotropic viscous Cartesian grid method based on a 2(N) tree data structure is developed. The method is capable of handling complex geometries automatically. In addition, viscous boundary layers can be computed with high resolution, using automatically projected high aspect ratio viscous layer grids. Compared with a widely used Octree data structure, the 2(N) tree data structure supports anisotropic grid adaptations in any of the coordinate directions. Therefore, key flow features such as shock waves, wakes, and vortices can be captured in a very efficient manner. To handle the adaptive viscous Cartesian grid, an implicit, second-order, finite volume flow solver supporting arbitrary grids has been developed. A linearity-preserving least-squares solution reconstruction algorithm is used to achieve second-order accuracy. Furthermore, several directional adaptation criteria are developed and tested, The overall grid generation, flow simulation, and grid adaptation methodology is then demonstrated for a variety of flow problems, including a case of supersonic turbulent flow over a high-angle-of-attack missile configuration.