Fundamentals of Cavitation

Cavitation is defined as the formation of one or more cavities in a liquid. The word “formation” can refer, in a general sense, to both the creation of a new cavity and the expansion of a preexisting gas pocket to a size where macroscopic effects, e.g., its shape and size, acoustic emissions, sonoluminescence, and erosive properties, can be observed. The cavity’s gas content refers to the liquid’s vapor, gas dissolved in the liquid, or combinations thereof. Cavitation usually occurs as a response when the pressure has been reduced sufficiently below the vapor pressure of the liquid or when the temperature has been elevated above the boiling point. In addition, chemical-, electrical-, and radiation-induced cavitation also exists. This book only considers the first case of cavity formation—that associated with a drop in pressure or a rise in temperature—in response to an acoustic field.