Dancing Raisins: Levitation and Dynamics of Bodies in Supersaturated Fluids*

Bodies immersed in gaseous fluids are natural sites for the nucleation of bubbles. These bubbles confer the bodies with additional buoyancy which can lift them upward against gravity. But a free-surface can clean the body of these lifting agents as the gas escapes which may result in plummeting, as the body begins the process anew. Experiments using fixed and free immersed bodies reveal fundamental features of force development. A continuum model which incorporates the dynamics of a surface buoyancy field is used to predict the ranges of body mass and size, and fluid properties, for which the system is most dynamic, and those for which body excursions are suppressed. Body rotations at the surface are found to be critical for driving periodic vertical motions of large bodies, which in turn can produce body wobbling and multi-period excursions.