Acoustic emission spectral analysis of ultrasound induced cavitation in insulating oil

The paper presents some spectral analysis results of acoustic emission observed during ultrasound driven round bottomed flask with fresh insulating oil inside. At suitable value of signal amplitude and frequency many of cavitation bubbles were observed. Collapsing bubbles were responsible for broadband noise included in acoustic emission signal spectra. To represent the cavitation intensity a simple cavitation indicator based on power spectral densities of acoustic emission signal was proposed.