The main purpose of this study is to study the aerodynamic mechanism of periodic roll motion of car body and provide engineering reference for car design and safety evaluation. A simplified roll motion model is established based on a real car model. The two-wheel centerline of the left-wheel symmetrical section is considered as the roll axis, and the overset mesh method was used to model the sinusoidal roll motion of the car. According to the experimental data, the frequency and maximum roll angle were set to be 10 Hz and 2.2°, respectively. A transient numerical solver based on the detached-eddy simulation method is employed. The accuracy of the numerical method is validated by means of the wind tunnel test. Due to the asymmetry of the movement, the aerodynamic change of the roll motion was obvious. It is found that the roll motion is closely related to the aerodynamic characteristics of the car. Because of the hysteresis effect, the phase of aerodynamic force on the car shifts and the most dangerous position of the car is obtained. In addition, the aerodynamic differences of the car parts are found, and the wake is analyzed in detail.

本研究的主要目的是研究车身周期性侧倾运动的气动机理，为汽车设计和安全评估提供工程参考。基于真实汽车模型建立了简化的侧倾运动模型。以左轮对称截面的两轮中心线为侧倾轴，采用重叠网格法对汽车的正弦侧倾运动进行建模。根据实验数据，频率和最大侧倾角分别设置为 10 Hz 和 2.2°。采用基于分离涡模拟方法的瞬态数值求解器。通过风洞试验验证了数值方法的准确性。由于运动的不对称性，横滚运动的气动变化很明显。发现侧倾运动与汽车的空气动力学特性密切相关。由于滞后效应，汽车上的气动力相位发生变化，从而获得汽车最危险的位置。此外，还发现了汽车零部件的空气动力学差异，并对尾流进行了详细分析。