Dynamics of Collapse of Free Surface Bubbles

Abstract

We experimentally study the collapse of cavities formedby bubbles of different radius R at the free surface of five different fluids. The tangential and normal velocities of the disturbance front on the bubble surface were measured andshown that the tangential velocities scale as the capillary velocity (σ/ρR)1/2. The total time for the completion of cavity collapse was measured and shown to scale as capillary time scale R3/2/(σ/ρ)1/2. We hence infer thatthe cavity collapse is dominated by surface tension and inertia with viscosity not playing a role in the regime of our investigation. Such a behavior of cavity dynamics is different from the behavior of jet velocity discussed by Sangeeth et.al.[9] wherein the jet velocity showed a clear viscous cut off. The rate of change of cavity volume was found to be constant with time, the implications of which needs to be investigated further.