Comparison between the effects of cavitation induced by twodifferent pressure-time shock waveform pulses

摘要

Acoustic cavitation generates very large localized pressures andntemperatures, and thus provides a mechanism whereby physical andnbiological effects are produced in a high-intensity acoustic field. Innthis work, we studied the influence of the temporal form of a pressurenpulse waveform on the destructive effects of transient cavitation. Twondifferent shock pressure-time waveforms with nearly the same acousticnenergy content were used. The first pressure waveform starts with antensile wave followed by a compressive one, and the second pressurenwaveform starts with a compressive wave followed by a tensile one. Thesentwo pressure waveforms are called direct and inverse-mode pulsesnrespectively. Based on the measurements presented in this work, we cannstate that, between the two types of shock pressure pulses studied, thendirect-mode pulse amplifies systematically tile cavitation effect. Thisnconclusion was achieved from a series of several quantitative andnqualitative experiments: cavitation bubble collapse time, disintegrationnefficacy of plaster balls (a kidney stone-mimicking material),nmacroscopic study of lesions in agar gel and in vitro isolated rabbitnliver tissue destruction. Considering these results and those obtainednby other research groups, we can express that the temporal form of anshock pressure pulse has a major role on the cavitation effects