Unstructured-Mesh Discretizations and Solvers for Computational Aerodynamics

An overview of current unstructured-mesh discretization and solution techniques is given. Cell-centered vs vertex-centered discretizations are discussed, as well as issues of grid alignment with flow features, higher-order reconstruction, and viscous-term formulation. With regard to solution techniques, implicit and multigrid methods are discussed, as well as efficient implementation on massively parallel computer hardware. Sample calculations are used to illustrate the importance of grid resolution and issues in solution accuracy. The examples are taken mostly from transonic flow calculations and are used to argue that unstructured-mesh technology has reached a level of maturity on a par with block-structured or overset-mesh methods in this area, although important outstanding issues remain for other application areas, such as high-speed flows.