Experimental study on interaction between a cavitation bubble and an oil layer–water interface

The interaction between a single laser-induced cavitation bubble and an oil layer–water interface is experimentally studied through high-speed photography technology. When oscillating near an oil layer–water interface, the bubble always migrates away from the interface with a jet pointing at the same direction. Three different motions of the interface are observed: interface experiencing subtle disturbance (case 1), interface presenting a deformation resembling an inverted hill (case 2), and interface developing a jet piercing the bubble (case 3). The effect of oil layer thickness on the bubble centroid migration and the inverted hill-shaped interface deformation are investigated as well. With a decreasing dimensionless bubble-interface distance, the effect of the oil layer on the bubble oscillation becomes more significant. In case 2 and case 3, the presence of the oil layer always weakens the migration distance of the bubble centroid.