镂空式车顶扰流板关键参数对两厢车空气阻力的影响

镂空式车顶扰流板已成为一种汽车造型设计的新思路，对整车空气动力性能也有极大的影响。为了研究镂空式车顶扰流板对整车空气阻力系数的影响，基于比亚迪某款带有镂空式车顶扰流板的两厢车型，以 CFD仿真为主要开发工具，分别研究了扰流板角度、镂空通道和 D 柱扰流板的影响，并与风洞试验结果进行对标。研究发现，镂空式车顶扰流板的角度减小，镂空通道与后风挡距离减小，以及 D 柱扰流板延伸长度增大均会导致顶部尾流增大，使尾流上下匹配关系发生变化。当上下尾流匹配性更好时，空气阻力系数更低。该研究结果可为后续镂空式车顶扰流板的开发提供经验。

Influence of Hollow Roof Spoilers on the Aerodynamic Drag of Hatchback Vehicles

The hollow roof spoiler has become a new trend in automotive styling design, significantly impacting the vehicle''s aerodynamic performance. To study the influence of the spoiler parameters on aerodynamic drag coefficient, CFD simulations were conducted to analyze cases with different spoiler angles, passage sizes, and D-pillar spoilers based on a BYD hatchback model with a hollow roof spoiler. The simulation results agree well with wind tunnel experiment results. It is found that the volume of the upper tail flow increases with a decrease in the spoiler angle, a reduction in the passage size or the addition of a D-pillar spoiler. A lower drag coefficient is obtained when the upper tail flow more effectively matches with the lower tail flow. The findings of this paper are valuable for guiding future designs of hollow roof spoilers.