Growth and collapse of a vapour cavity near a free surface

An approximate integral-equation approach is used to model the growth and collapse of a vapour cavity in close proximity to an initially plane free surface. By comparison with experiment, it is shown to predict all the salient features of the bubble and freesurface interaction, provided that the complete nonlinear Bernoulli pressure condition is applied on both surfaces. Features observed and predicted include the formation of an accelerating liquid jet in the bubble and a pronounced spike in the free surface during the collapse phase of the bubble's life. If the bubble is initially sufficiently close to the free surface, it will become ‘entrained’ in the raised free surface with a veneer of liquid separating the two free surfaces.