Abstract
To clear the time-dependent feature of the cavitation pattern within small separation distances between the viratory horn tip and the glass wall, we study the periodic behavior of the cavitation bubbles and bubble clouds on the surface of horn tip, the sign of shock waves and the corresponding erosion dents for various concentrations C of the ethanol aqueous solutions and the separation distance S, using by acoustic cavitation device with 20kHz in frequency. It is found that the area of the cavitation region and the bubble clouds with time depend on C and S.