车尾凹坑非光滑表面气动减阻分析与优化设计

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。

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

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 dynamics) 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 simulation, the Kriging model was established. The credibility of the model was verified and global optimization 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 aerodynamic performance and provides non-smooth surface drag reduction and optimization with theoretical basis and reference.