The acoustic signature of the vortex cavitation bubbles can be characterized during inception, growth, and collapse. Growing and collapsing bubbles produced a sharp, broadband, popping sound. However, some elongated cavitation bubbles produce a short tone burst, or chirp, with frequencies on the order of 1 to 6 kHz. The frequency content of the acoustic signal during bubble inception and growth were related to the volumetric oscillations of the bubble and vortex dynamics coupling. A relationship was also found between the frequency of the oscillations and the flow and water quality conditions.http://deepblue.lib.umich.edu/bitstream/2027.42/84225/1/CAV2009-final183.pd