Relation Between the Predominance of Acoustic Resonance Noise and Air Flow in Muffler

The interaction phenomena of the internal flow and the acoustic resonance noise in expansion cavity type mufflers was investigated. The generation conditions of this phenomena and the predominance of acoustic resonance noise were examined. According to the distribution of fluctuating velocity generated in the cavity, the location where the vortexes were generated in the cavity and the amplifying process of the vortex rings were clarified.