A stochastic method is used to predict wind noise of a simplified automobile head shape. In the method, computational region is divided into two parts: One is source region, and the other is propagation region. In the source region, turbulent fluctuation velocities are synthesized with a stochastic model. In the propagation region, linearized Euler equations with source terms are solved and sound waves spread out. Compared with direct simulation method, the method has advantage of less computational cost and memory. Numerical simulations agree well with experimental data. It is shown that the method is feasible for automobile wind noise prediction, It laid a foundation for actual automobile shape wind noise prediction.

Three kinds of training algorithms for efficient global optimization(EGO) method are investigated.A kind of training algorithm based on low-discrepancy sequences is proposed to reduce randomness of EGO method.Performance of EGO method depends on a good training algorithm.Since training problems in EGO are non-convex and non-smooth,meta-heuristic algorithms,random algorithm and low-discrepancy sequences are chosen to address five benchmark optimization problems and two aerodynamic shape optimization problems.In these problems,differential evolution algorithm was found the best in meta-heuristic algorithms.Training algorithm based on low-discrepancy sequences can effectively reduce randomness of EGO method and Faure sequence has the best performance.

Simulation of trailing edge noise based on stochastic noise generation and radiation(SNGR)method is shown.The SNGR method combines stochastic method with computational fluid dynamics,which gives acceptable noise result with relatively low computation cost.Reynolds averaged Navier-Stokes(BANS)equations arc solved by finite volume method.Acoustic perturbation equations are Bolved by finite difference method.Numerical scheme is a dispersion-relation-preserving(DRP)scheme.Non-reflection far.field boundary eonditions are utilized.A two.dimensional flat plate and an NACA0012 airfoil are simulated and compared with reference results.It is shown that the program predicts correctly trailing edge noise.

With Lennard-Jones interaction potentials a GSS-3 molecular model is proposed to study transport properties of gas,such as coefficient of viscosity,self-diffusion and diffusion of molecules.The model is applied to unstructured direct simulation Monte Carlo method.Numerical results confirm feasibility of the model.

Navier-Stokes equations are solved numerically to simulate vortex motion in separated flows using detached-eddy simulation (DES) method in Saplart-Allmaras one equation model. A finite volume scheme is employed. Spatial discretization is performed with Jameson central scheme. Time integration is implemented by a dual time-stepping approach. Vortex structures of flow over a circular cylinder or a stall airfoil simulated agree well with physical analyses and experimental data.

A numerical method applicable to unstructured mesh is proposed to compute 3D hypersonic ionized and radiating flowfields in thermo-chemical nonequilibrium. The flowfield is described with multi-specy N-S equations. The chemical model includes 11 species(O₂, N₂, O,N, NO, NO⁺, N⁺, O+, N₂⁺, O₂⁺, e^-) and 20 reactions. For thermal nonequilibrium effect, a two temperature model is considered. Radiation transfer equation (RTE) is solved with finite volume method. Numerical result on MUSES-C is shown and compared with referenced data. Influence of radiation on flowfield is discussed.