不同侧风角作用下Ahmed模型空气动力学特性分析

通过3种数值模拟方法的对比分析，得到最优的模拟方案，故采用分离涡方法对Ahmed模型气动特性进行研究，分析了不同侧风角对钝体尾流的涡量、湍流强度、压力及流线的分布规律的影响，得到了力和力矩系数的变化特征，总结了尾流倾斜角度随侧风角变化的综合公式。研究结果表明，侧风角对钝体尾流特征参数影响不是单调的，在侧风角为30°时钝体尾部涡量最大；钝体尾流倾斜角度与气动力系数随侧风角的增大而增大；侧风角50°时的钝体背部迎风侧压力和头部平均速度也达到最大值。研究结果可以为复杂横向来流条件下汽车运行的安全性和稳定性提供一定依据。

Aerodynamic characteristics of Ahmed model under different crosswind angles

Through the comparison and analysis of three numerical simulation methods, the optimal simulation scheme is obtained. Therefore, the separation vortices method is used to study the aerodynamic characteristics of Ahmed model, and the influence of different side wind angles on the distribution law of vorticity, turbulence intensity, pressure and streamline of blunt body wake is analyzed. The variation characteristics of force and moment coefficient are obtained, and the comprehensive formula of tail inclination angle changing with side wind angle is summarized. The results show that the influence of the side wind angle on the characteristic parameters of the blunt body wake is not monotonous, and the rear vorticity of the blunt body is the largest when the side wind angle is 30°. The inclination angle and aerodynamic coefficient of the wake of the blunt body increase with the increase of the side wind angle. Back windward side pressure and average head speed of the blunt body also reach maximum values at a side wind angle of 50°. The conclusions can provide some basis for the safety and stability of vehicle operation under Complex Transverse inflow conditions.