DOI: 10.1615/TSFP6
Experimental Investigation of Automobile Sunroof Buffeting Shear Flows
RESUMO
The automobile sunroof buffeting is the tonal noise of a low frequency around 20Hz. It occurs due to the acoustic feedback process between the shear layer detached from the leading edge of sunroof opening and the Helmholtz resonator-like property of a car cabin. In this work, PIV visualization technique is applied to the unsteady flow field around sunroof opening of a SUV in the full-scale automotive wind tunnel in order to find out buffeting mechanism. A phase-marked PIV measurement method, in which image and sound pressure are recorded simultaneously, and a phase-rearrangement post-processing program were developed for capturing noise-related velocity fields without expensive synchronization systems. Through this study, some characteristics of the real-car sunroof shear layers under various deflector conditions were identified and these results can provide insights into the noise reduction mechanism of the tube-type deflector.