The effect of buffeting noise in passenger cars

Abstract

This paper presents the effect of buffeting noise in passenger cars in real conditions at variable speed. When a back window is 25% open the buffeting noise is not perceived; it starts to be perceived when the window is 50% open, with a resonance frequency of 15.6 Hz at a speed of 80km/h, but is not irritating because the pressure level is low (110.2dB). When the window is rolled down at 75%, two airflows appear inside the car: one from the top of the upper interior zone and a second one from the central interior zone. The effect of buffeting noise is then clearly perceived with a resonance frequency of 16.4Hz at a speed of 80km/h and a pressure level of 119dB, increasing to 19.5Hz for a speed of 110km/h and a pressure level of 122dB. At a speed higher than 130-140km/h, the buffeting noise disappears, depending on the car model. For Opel Corsa the effect of buffeting noise appears only in one speed range, while for Peugeot and BMW models three different speed ranges are identified: for generation, persistence and disappearance of buffeting noise.