Abstract: The numerical simulation of the flow field of the smooth surface MIRA stepped back model was carried out and verified by using the method of computational fluid dynamics. Based on the drag reduction theory of bionic non-smooth surface, the location and size of the concave non-smooth element were determined. The influence of the non-smooth element structure on the drag reduction characteristics was simulated and analyzed. The structure factors of concave element were optimized by orthogonal experimental design. The simulation results show that the drag reduction rate of the optimal structure combination can reach 10.54%. Finally, from three aspects such as pressure drag, induced drag and friction, the drag reduction mechanism of the optimal structure combination of concave non-smooth element before and after improvement was analyzed and compared; the drag reduction effect for the body was significantly improved.

Key words: vehicle engineering, non-smooth element, drag reduction characteristics, optimization

摘要： 利用计算流体动力学的方法，对光滑表面MIRA阶梯背模型进行了外流场数值模拟与试验验证；根据仿生非光滑表面减阻理论，确定了凹坑 型非光滑单元体的布置位置及尺寸，并对凹坑型非光滑单元体结构因素对减阻特性的影响进行仿真分析；并基于正交实验设计对凹坑型单元体的 结构因素进行优化，仿真表明最优结构组合的减阻率可达10.54%；最后从压差阻力、诱导阻力和摩擦阻力3个方面对凹坑型非光滑单元体最优结构 组合改进前后的减阻机理进行了对比分析，显著提高了车身的减阻效果。

关键词: 车辆工程, 非光滑单元体, 减阻特性, 优化