Abstract: The external flow field and the interior noise of the passenger compartment of a SUV are calculated by computational fluid dynamics and statistical energy method respectively, and the sound pressure level (SPL) curve at drivers head region is obtained. Based on the simulation results of original vehicle model, rear view mirror and wiper are modified, and the noise evaluation and comparison between before and after modifications are carried out by numerical simulation and road test. The SPL curves obtained by simulation and road test have the same overall tendency, showing the effectiveness of simulation results. The results of simulation indicate that both rear-view mirror and wiper modification schemes have noise reduction effects in full frequency range, in which the maximum reduction amplitude in SPL reaches 5.6dB(A) and the total SPL with both schemes reduce by 1.5 and 1.8dB(A) respectively. The results of road test show that in high frequency segment with relatively low noise, the SPL after modification has apparent fall, with the maximum reduction amplitude reaching 5.1dB(A) in some high-frequency band. And the total SPL with both modification schemes reduce by 0.2 and 0.7dB(A) respectively, demonstrating the effectiveness of modifications and the feasibility of study method.

Key words: rear view mirror, wiper, wind noise optimization, numerical simulation, road test