How to calculate turbulent flow by solving Navier-Stokes equations on unstructured grids is investigated.The cell-center finite volume method is used to solve N-S equations.Baldwin-Barth one equation turbulence model is chosen to calculate turbulent flow which is especially suitable to unstructured meshes.The model consists of a single advection-diffusion equation with a source term.In order to solve this model equation on irregular grids,an explicit finite-volume scheme is delivered,and its time step limiting condition is obtained by analyzing stability of the scheme which possesses a source term.At the end,the numerical examples,such as turbulent flow around flat,RAE-2822 foil and multi-element foil,are given which verify the validation of the computational method.

An approach of exact controllability combined with non-overlapping domain decomposition associated to the physical layer structure of air and coated material media is presented for simulations of the scattering of planar waves in 2-D coated aerodynamic shapes.Domain decomposition with non-matching finite element meshes at the interface is introduced,which allows to use different numbers of grid points required by different media.The conditions of compatibility at the interfaces between each subdomain are satisfied weakly by a Lagrange multiplier technique.The whole structure of the algorithm includes one outer loop for capturing time periodic solutions based on exact controllability and one inner loop for domain decomposed solutions through a treatment of Lagrange multiplier.Numerical results of the scattered fields are presented and compared for both perfectly conducting and coated aerodynamic shapes like 2-D airfoils,which reveal the effect of the coated layer.