车尾凹坑非光滑表面气动减阻分析与优化设计

Analysis and Optimization Design of Aerodynamic Drag Reduction on Vehicle Rear End by Using Pit Non-Smooth Surface

以凹坑型非光滑车身尾部气动特性为研究对象,探讨了一种将参数化建模、CFD计算和数值寻优方法相结合的非光滑表面气动减阻优化方法。通过分析凹坑型非光滑单元矩形阵列的气动减阻效果,以矩形排布和非光滑单元体尺寸作为优化对象,采用拉丁超立方抽样方法进行试验设计选取样本点。利用CFD仿真得到样本点的响应值,根据响应值建立了Kriging近似模型。在验证了近似模型可信度的基础上,以近似模型为基础进行全局优化。优化结果表明:车辆尾部凹坑单元体矩形排布最大减阻率可达7.9%,较大程度地改善了空气动力学性能。研究结果为汽车非光滑表面减阻和优化提供了理论依据和参考。

Taking aerodynamic drag characteristics of the pit non--smooth surface rear vehicle body as the research object,a kind of optimization method about aerodynamic drag reduction of non-- smooth surface was discussed by combining parametric modeling, the CFD（computational fluid dy- namics） calculation and the numerical optimization method. By analyzing aerodynamic drag reduction effect of rectangular arrangement of pit non--smooth unit body, setting rectangular arrangement and non--smooth unit body as optimization objective,and the Latin Hypercube Sampling method was used to select sample data. The response values corresponding to the sample were achieved by CFD simula- tion, the Kriging model was established. The credibility of the model was verified and global optimiza- tion was carried out by optimization algorithm. The results show that the maximum drag coefficient of the rectangular pit arrangement of the vehicle rear end is as 7.9 % ,which greatly improves its aerody namic performance and provides non--smooth surface drag reduction and optimization with theoretical basis and reference.