Noise generated by a turbulent grazing flow over a cavity at low Mach number: an application to car door cavities.

Noise generated by a turbulent grazing flow over a cavity at low Mach number: an application to car door cavities. Noise produced by turbulent grazing flow over a generic cavity representing car door cavities was measured in a semi-anechoic wind tunnel. Two cavities were studied: one 50 mm large (dimension perpendicular to the airflow), functioning as a Helmholtz resonator, reaching sound pressure levels of 136 dB at 1776 Hz, for a downstream velocity of 54 m/s. The other, of scale 250 mm could not be regarded as a Helmholtz resonator although resonance occurred at 1902 Hz, at a level of 125 dB, for the same velocity. In both cases, noise was caused by Kelvin-Helmholtz instabilities in the mixing layer. To cite this article: A. Da Silva et al., C. R. Mecanique 337 (2009). (c) 2009 Academie des sciences. Publie par Elsevier Masson SAS.