基于响应面模型的汽车气动特性优化

Automotive Aerodynamic Characteristics Optimization Based on Response Surface Model

为综合改善某车型气动力系数,提出一种外形优化设计方案。首先采用Realizablek-ε湍流模型对汽车无侧风工况进行数值模拟,并结合风洞试验验证了仿真模型的可靠性。在此基础上,研究不同侧风角对汽车气动特性的影响,并以横摆角12°时的气动力系数为优化参考基准,通过均匀拉丁超立方抽取样本进行流场计算,应用响应面模型近似汽车造型参数与气动力系数的对应关系,基于遗传算法得到Pareto前沿解。最终确定了4种优化方案,最大分别使阻力系数降低2.6%、侧力系数降低6.54%、升力系数趋于负值,有效改善了汽车的气动特性。

In order to improve vehicle aerodynamic coefficients comprehensively,this paper proposed a shape optimization design scheme.Firstly,vehicle without crosswind was simulated numerically by using realizable k-εturbulence model.The reliability of the simulation model was verified by wind tunnel tests.On this basis,the influence of different crosswind angles on the aerodynamic characteristics was studied,the aerodynamic coefficients of yaw angle of 12°were taken as the reference benchmark for optimization,samples were extracted by uniform Latin hypercube for flow field calculation,the response surface model was used to approximate the corresponding relationship between automobile modeling parameters and aerodynamic coefficients,the Pareto front solutions were obtained based on the genetic optimization algorithm.Finally,4 optimization schemes were determined,which reduced the drag coefficient by 2.6%,the lateral force coefficient by 6.54%,and the lift coefficient tends to be negative,effectively improving the aerodynamic characteristics of the vehicle.