In this paper, a new tool is proposed to carry out acoustic cavitation monitoring and to have an overview of its effects in applications. After a brief review of the cavitation characterization techniques, it is shown that cavitation noise is a suitable and accurate indicator of the cavitation activity induced in a liquid. In the first part of this study, the origin of the first spectral component of the cavitation noise is discussed. The f/2 and 2 f component evolution measurement at a driving frequency around 1 MHz confirms Neppiras' ones and gives an indicator of the cavitation inception. In the second part, the cavitation noise spectrum distortion is considered as a function of the acoustic power transmitted to the liquid in order to obtain an indicator of cavitation activity. In the last part, this new tool is used to bring to the fore the hysteresis effect associated with the cavitation. An experimental correlation between cavitation noise power measurement and the sonochemical activity in an oxidization process is also presented.

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This paper deals with the inertial cavitation of a single gas bubble in a liquid submitted to an ultrasonic wave. The aim was to calculate accurately the pressure and temperature at the bubble wall and in the liquid adjacent to the wall just before and just after the collapse. Two different approaches were proposed for modeling the heat transfer between the ambient liquid and the gas: the simplified approach (A) with liquid acting as perfect heat sink, the rigorous approach (B) with liquid acting as a normal heat conducting medium. The time profiles of the bubble radius, gas temperature, interface temperature and pressure corresponding to the above models were compared and important differences were observed excepted for the bubble size. The exact pressure and temperature distributions in the liquid corresponding to the second model (B) were also presented. These profiles are necessary for the prediction of any physical phenomena occurring around the cavitation bubble, with possible applications to sono-crystallization.