An unstructured/structured multi-layer hybrid grid method and its application

摘要

A multi-layer hybrid grid method is constructed to simulate complex flow field around 2-D and 3-D configuration. The method combines Cartesian grids with structured grids and triangular meshes to provide great flexibility in discretizing a domain. We generate the body-fitted structured grids near the wall surface and the Cartesian grids for the far field. In addition, we regard the triangular meshes as an adhesive to link each grid part. Coupled with a tree data structure, the Cartesian grid is generated automatically through a cell-cutting algorithm. The grid merging methodology is discussed, which can smooth hybrid grids and improve the quality of the grids. A cell-centred finite volume flow solver has been developed in combination with a dual-time stepping scheme. The flow solver supports arbitrary control volume cells. Both inviscid and viscous flows are computed by solving the Euler and Navier-Stokes equations. The above methods and algorithms have been validated on some test cases. Computed results are presented and compared with experimental data.