Spectral change in acoustic pressure and cavitation inception

Acoustic pressure spectra were measured against the excitation level of the piezoelectric transducer in order to investigate the relationship between acoustic spectra and cavitation inception at an excitation frequency of 20 kHz. Measurements-were conducted on degassed and nondegassed distilled water using an acoustooptic detection system. The results of the measurements suggest that the observation of n/2 (n: 3, 5, 7 ...) order subharmonics is useful to monitor the inception of transient cavitation.