Hystérésis et réduction de sons auto-entretenus commandées par effet Coanda

Abstract

An air flow crossing two baffles in tandem inside a duct, generates strong self-sustained tones. Four radial slots created on the upstream baffle, leads to a large hysteresis loop of the sound pressure level when velocity varies, the second branch of which corresponds with a reduction of the self-sustained tones. Measurements of velocity show that a Coanda effect happens on the jets issued from the slots, which induces this flow behaviour.