A cartesian/unstructured hybrid grid solver and its applications to 2D/3D complex inviscid flow fields

摘要

A Cartesian/unstructured hybrid grid solver is presented for numerical simulations of inviscid flows around complex geometries. The unstructured grids are applied only near complex configurations to simulate the realistic geometries, while the Cartesian grids are utilized to discretize almost enitre area of outer flow fields. The present algorithm overcomes the disadvantage of requiring more memory storage and CPU time for the fully unstructured grid solvers, and solves the difficulty of describing curve boundaries for fully Cartesian grid methods. A simplified Quadtree(2D)/Octree(3D) method is introduced to generate 2D and 3D hybrid mesh. Based on the non-oscillatory, non-free-parameter dissipative finite difference (NND-FD) scheme, a NND finite volume (NND-FV) scheme is developed on unstructured grids and is coupled with NND-FD scheme as a hybrid one to solve Euler equations. The numerical experiments demonstrate that the present scheme is quite accurate, efficient and robust.