Study on the sunroof buffeting suppression with a notched flat deflector

Buffeting is a wind noise of low frequency but high level, which makes against the comfort and safety ability of the vehicle. A simulation method of sunroof buffeting was presented and validated by the road test. The simulation method was then employed to investigate the sunroof buffeting characteristics of the vehicle with a castled deflector with the vehicle speed ranging from 30kph to 90 kph. The results showed that the highest sunroof buffeting level occurred at 70kph, with a value of 135.9 dB. To suppress the sunroof buffeting, a notched flat deflector was designed to replace the castled deflector. In particular, the influence of the deflector gap on sunroof buffeting was studied. The results revealed that the deflector had a great influence on sunroof buffeting and the optimal parameters, gap and a, were determined. With the new designed notched flat deflector, the sunroof buffeting of the vehicle was reduced to 97.9 dB. In other words, the sunroof buffeting was completely eliminated.