An experimental study has been carried out in order to investigate the noise radiated by various
cavitating sources to determine the validity of noise measurements for detecting the onset of
cavitation. Measurements have been made measuring the noise radiated by a number of
configurations in a water tunnel at various operating condition to determine the onset of cavitation.
The measurements have been conducted over a frequency range of 31.5 Hz to 31.5 kHz in one‌third octave bands. The onset of cavitation was measured visually through a Perspex side of the
working section of the water tunnel. Moreover, a theoretical estimate of the pressure radiated from
the cavitation nuclei at their critical radii and frequency was presented.

Tests indicated that, generally, at the point of visual inception there was a marked rise of the
sound pressure level in the high-frequency noise, whilst the low-frequency noise increased as the
cavitation developed. This finding was supported by the theoretical estimate of the pulsating
frequency of cavitation nuclei. The results illustrated that the visual observations of inception
confirm the noise measurements.