A finite element/finite volume mixed solver on hybrid grids

The Discontinuous Galerkin (DG) finite element methods (FEM)have shown to be of high-accuracy for simulating complex flows with shock waves,especially viscous effects near boundary layers. However,they require more CPU time and memory storage than finite volume methods. Onthe other hand, the finite volume methods face thedifficulty of predicting the heat flux over complex geometries, especiallyon unstructured grids. An optimal choice is to combine the two kinds ofmethods to take all their advantages.So in this paper, a finite element/finite volume mixed solver is presented.Within the mixed solver, the previous DG-FEM solver on non-orthogonal gridsis used near the boundary layers to capture the viscous effects, while thefinite volume solver is adopted in the outer field to save the CPU time and memory storage. The numerical flux on the interface of FE/FV solvers is solvedconservatively to guarantee the transformation of FE/FV solvers smoothly.The mixed solver is validated by two hypersonic cases, e.g. hypersonic flowsover a blunt cone and double-ellipsoids. The computational results, includingflow patterns and heat flux distributions, show good agreements withexperimental data, and the comparison on CPU time and memory storagedemonstrates the higher efficiency over the finite element solver.