Cavitation nuclei and bubble formation - A dynamic liquid-solid interface problem

A model of the formation of cavitation nuclei is developed assuming local detachment of the liquid at locations of concave solid surface topography. The detachment is attributed to diffusion of gas molecules into the interfacial liquid, where the liquid-solid bonds are strained due to interfacial tension in the liquid. Calculations indicate that attached interfacial voids may grow into stabilized cavitation nuclei as a consequence of broad-band resonance, excited by external sources of noise or vibration in the whole range of frequencies up to the MHz regime. The gas content in the liquid and the amplitude and frequency of the sound field determine a balance between rectified diffusion of gas into the void and diffusion out of it due to the excess pressure in the void. In strong acoustic fields and in supersaturated liquids the voids may grow into bubbles that detach and form free gas bubbles. [S0098-2202(00)01503-0].