Abstract: When a car runs at a high speed more than 100 km/h, the aerodynamic noise produced by the interaction of air flow and car body plays a leading role in the noise contribution of the vehicle, so it is very important to control the aerodynamic noise source outside the vehicle. The correlation between aerodynamic of the SUV rear mirror arm length and the interior noise environment of the vehicle was studied by the experimental method. The results show that the relationship between the parameters of the rear mirror arm length and sound energy is logarithmic. The relationship between the parameters of the rear mirror arm length and articulation is logarithmic, too. The relationship between the parameters of the rear mirror arm length and loudness follows quadratic equation. When the rear mirror arm length is controlled to be between 40~50 mm, the sound pressure level is reduced by 0.6 dB(A), the relative improvement is about 0.5%, the articulation is increased by 5.4% AI, the relative change is 9%~14%, the loudness is reduced by 0.5~0.6 sone, and the relative improvement is about 1.7%~2.1%. The technical method of the controlling aerodynamic noise in the rear mirror arm length has been obtained preliminarily. The technology reduces the noise in the car and improves the sound quality of the SUV.

Key words: aerodynamic noise, acoustics, wind tunnel, rear mirror arm length