汽车风洞双车试验来流湍流特征研究

基于自主研发的真实道路来流参数测量系统，对多地区、多场景真实道路行驶来流湍流强度进行了测试，发现车辆道路行驶时来流湍流强度远高于风洞水平，道路平均湍流强度为4%，沿海地区湍流强度最高可达20%，在跟车或超车时湍流强度可达 28%。在汽车风洞内模拟了道路行驶跟车、超车等试验场景，对测试车辆气流环境进行了采集分析。结果表明，跟车和超车时，后车来流湍流强度较高且伴随有速度损失，湍流强度及速度损失大小与前车尺寸和跟车距离有关，湍流强度分布范围为2%～33%，与道路实测相当，且速度损失最大为19%。进一步探究了前车放置角度、风洞风速对后车来流湍流强度的影响规律，建立对后车来流湍流强度定量调节的方法。完成了双车风噪测试，结果表明，风洞内高湍流强度环境车内风噪测试调制频谱结果与道路行驶测试结果相符，车内风噪频谱曲线差异主要集中在小于70 Hz的低频段。

Study on Incoming Turbulent Flow Characteristics Based on Two-Vehicle Test in Automotive Wind Tunnel

Tests were conducted with the self-developed measurement system in multiple areas and scenarios to obtain the parameter values in the real-road air flow environment. The analysis revealed that the vehicles on the road experience a higher turbulent intensity of the incoming flow than those tested in the wind tunnel. The average turbulent intensity was 4% and the intensity reached as high as 20% in the coastal areas and 28% when vehicles followed or overtook each other. Vehicular tests of following and overtaking were carried out in the automotive wind tunnel, and the airflow condition of the test vehicles was collected and analyzed, showing that the incoming turbulence intensity of the following vehicle was higher which caused a decrease in speed. The turbulence intensity and velocity loss are related to the size of the followed vehicle and the following distance. The turbulent intensity distribution ranges from 2% to 33% and the maximum velocity loss is 19%. The influence of the front vehicle''s placement angle and wind tunnel wind speed on the turbulence intensity of the rear vehicle was further investigated and a method to quantitatively adjust the turbulence intensity of incoming flow was developed. The two-vehicle aero-acoustic test has been completed in the wind tunnel. The results show that the modulation spectra of cabin noise in the high turbulence intensity environment are consistent well with the on-road test results. The differences in the spectrum curves of cabin noise are mainly concentrated in the low frequency range of less than 70 Hz.