Numerical Simulation Of The Flow Deflectorsbased On Hybrid Cartesian Method

In this thesis, the hybrid Cartesian grid(HCG) method, coupled with a flow-field numerical solver for 2D Reynolds-Averaged Navier-Stokes(RANS) equation base on finite volume method, is employed for numerical simulation and optimization of the flow deflectors. The research includes following parts in specific:First, the hybrid Cartesian grid which consists of body-fitted structured grid and Cartesian grid in flow field is especially efficient in dealing with complex geometries. And the generation of HCG is highly automatic.Then, a compressible RANS equation solver for 2D viscous flow is presented based on HCG method and finite volume scheme. The HLLC Riemann Solver and Venkatakrishnan limiter is used for the computation of convective flux, and second-order cell centered scheme for viscous flux. The LU-SGS implicit time-stepping method is employed. The k-ω SST two-equation model is used for turbulence modeling.Finally, the computational result of NACA0012 airfoil is compared with experiment data to validate the accuracy of the numerical solver. And the flow field of NACA0012 airfoil with flow deflectors is computed. Compared with the results of clean airfoil, the flow deflectors prove to be effective in flow separation control, stall delay and increase of lift coefficient. Then genetic algorithm is applied to optimize the parameters of the flow deflectors.The body-fitted structured grid on solid wall is fixed in optimization and the Cartesian grid in flow field can be generated automatically, which indicate that hybrid Cartesian grid system is quite convenient, highly efficient and time-saving especially when dealing with multi-objects problems.