应用计算流体动力学方法分别对带光滑底部和真实底部结构的某轿车进行侧风气动特性对比分析。结果表明:汽车底部结构对气动力影响显著,与光滑底部相比,实际底部结构使尾涡扩散区增大,车底流速减小,导致气动力增加;加装车底阻流板能改善侧风状态下汽车的底部、尾部和背风侧的流场结构,降低整车气动力,特别是气动升力。模型风洞试验验证了所采用数值分析方法的可靠性。本研究对指导汽车底部结构设计和侧风稳定性分析具有较好的参考价值。
Computational fluid dynamics is applied to the comparative analysis on the aerodynamic characteristics of a car with real and smoothed underbody structure respectively under the action of crosswind. The results show that the underbody structure of vehicle has significant effects on aerodynamic forces,and adding an underbody spoiler can improve the flow field structure of underbody,wake and lee side in crosswind and reduce the aerodynamic forces,in particular,the lift force of vehicle. Scale model wind tunnel test verifies the reliability of the numerical analysis method adopted. The outcomes of the study are valuable references for the guidance of vehicle underbody structure design and the analysis on vehicle stability in crosswind.