侧风状态下车内气动噪声分析与优化

Analysis and Optimization of Interior Aerodynamic Noise from a Vehicle in Crosswind Conditions

在侧风作用下,车内的气动噪声值会显著增大。为了降低侧风作用下乘用车内部的气动噪声,以某SUV为研究对象,利用计算流体力学对整车外流场进行计算得到乘用车表面压力和速度,将整车模型逆时针转动10°来模拟侧风。根据流场计算结果,基于Lighthill声类比法有限元分析对车内气动噪声进行计算,并利用风洞试验验证计算结果的正确性。通过对A柱、底盘两处进行优化设计,将优化后车内噪声计算结果与优化前进行对比分析。分析表明:改善A柱表面曲率,使A柱表面部分结构与前风挡平行,并将其宽度设为10 mm,车内中高频段声压级降低约1.08 dB(A),语音清晰度提高1.78%;在汽车底盘处增加矩形齿气坝,中高频段的声压级降低约0.55 dB(A),语音清晰度提高0.33%。

Under the effect of side wind,the aerodynamic noise value inside the vehicle will increase significantly.To re-duce the aerodynamic noise inside the passenger car under the effect of side wind.This paper takes an SUV as the research object.Computational fluid dynamics is used to calculate the external flow field of the whole vehicle to obtain the surface pressure and velocity of the passenger car.The vehicle model is rotated counterclockwise by lo degrees to simulate the side wind.According to the results of the flow field calculation,the aerodynamic noise inside the vehicle is calculated based on the finite element analysis of the Lighthill acoustic analogue method.And the wind tunnel test is used to verify the cor-rectness of the calculation results.By optimizing the design of the A-pillar and chassis at two places.The calculation re-sults of interior noise after optimization are compared and analyzed with those before optimization.The analysis shows that:improve the curvature of the surface of the A-pillar,make the surface of the A-pillar part of the structure parallel to the front windshield,and set its width to lo mm,the sound pressure level in the middle and high frequency bands inside the car is reduced by about 1.08 dB(A),and the clarity of speech is improved by 1.78%;add a rectangular tooth air dam in the chassis of the car.The sound pressure level in the middle and high frequency bands is reduced by about O.55 dB(A).Speech intelligibility is improved by 0.33%.