Vortex Cavitation

Cavitation is normally defined as the formation of the vapor phase in a liquid. The term cavitation (originally coined by R.E. Froude) can imply anything from the initial formation of bubbles (inception) to large-scale, attached cavities (supercavitation). The formation of individual bubbles and subsequent development of attached cavities, bubble clouds, etc., is directly related to reductions in local fluid pressure below some critical value. This pressure is in turn is associated with dynamical effects, either in a flowing liquid or in an acoustical field. Cavitation is distinguished from boiling as the former is induced by the lowering of hydrodynamic pressure, whereas the latter is induced by the raising of vapor pressure to some value in excess of the hydrodynamic pressure. The two phenomena are of course related. Cavitation inception and boiling can be compared in terms of the vapor-bubble dynamics of sub-cooled and super-heated liquids (Plesset 1957). Quite often a clear distinction between the two types of phenomena cannot be made. This is especially true for cavitation in liquids other than cold water.