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采用大涡模拟(LES)的计算方法,对车外后视镜不同边缘结构引起的外部流场和镜后车身表面监测点处的气动噪声进行了数值仿真.研究表明:不同的镜罩边缘结构在较大程度上影响了流经后视镜罩的气流速度和流线方向,对后视镜后部流场和监测点处声压级产生较大影响.相较于原模型的光滑边缘结构,模型1后部流场涡团更远离车身表面,有利于降低气动噪声,某监测点1/3倍频程中心频率处声压级最大降幅接近10dB;模型2后部流场涡团产生分离,并更靠近车身表面,反而使气动噪声增大.模型1的镜罩边缘结构改进方案对车外后视镜-A柱区域的流场和气动噪声都有较好的改善.
A large eddy simulation (LES) method is used to simulate the external flow field caused by the different edge structures of the exterior mirrors and the aerodynamic noise at the monitoring point of the mirror body surface. The results show that different mirror edge structures Which greatly influenced the airflow velocity and streamline direction flowing through the mirror hood, which had a great impact on the sound pressure level at the rear flow field and the monitoring point of the rearview mirror.Compared with the smooth edge structure of the original model , The eddy of the flow field in the rear of model 1 is far away from the body surface, which is helpful to reduce the aerodynamic noise. The maximum amplitude decrease of the sound pressure level at the center frequency of 1/3 octave of a monitoring point is close to 10dB; , And closer to the body surface, but the aerodynamic noise increases.Model 1 mirror edge structure improvement scheme for the exterior mirror - A column area of the flow field and aerodynamic noise have better improvement.