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.It generates the body-fitted structured grids near the wall surface and the Cartesian grids for the far field.In addition,the triangular meshes are regarded as an adhesive to link each part of grids.The grid combination methodology is discussed,which can smooth hybrid grids and improve the quality of the grids.A uniform type of data is defined to manage and arrange grid data.Using the centered finite volume method,the inviscid and viscous flow allows computation by solving the Euler and Navier-Stokes equations.The computational results prove that grid generation and flow calculation are correct and feasible.

A method for the adaptive refinement of a Quad/Cartesian grid for the solutions of the Euler and N-S equations is presented.An adaptive Quad/Cartesian hybrid grid method,which retains the advantages of the Cartesian grid approach and, at the same time, touches the viscous flow problems,is provided.The body fitted Quad grids are generated around the body and the Cartesian grids are used in the remains of the flow field.The flow solver of the Euler and N-S equations is performed by a conventional algorithm,including the finite volume method and the Runge-Kutta time-stepping scheme.The grid adaptation and the flow solver achieve reasonable efficiency and accuracy with minimum computer resources.Based on the above approach,the numerical analysis of flows around the single-element and the multi element airfoils is given.The numerical results presented show the flexibility of this approach and the accuracy attainable by the solution-based refinement.

A new unstructured Cartesian cutted grid generation method is introduced. The grid generation of some airfoils and wing is performed with the tree data structure. Euler equations are solved using the cell-centred finite volume method. The results of flow field computation are in agreement with the experiments. These facts show that the grid generation and the numerical calculation approach is correct and reasonable. Based on the above work, a flow field numerical simulation of wing and store separation is finished. This process provides a new way and tool for the more accurate solver of the unsteady flow problem.