Interfacial Jets

A fluid-fluid interface between two immiscible liquids of different densities is formed; here on top is water and below a denser liquid (hydrofluoroether, also known as HFE). HFE is 1.5 times denser than water yet both liquids have very similar viscosity. An explosively expanding bubble with a maximum bubble radius of 0.68 mm is generated by vaporizing the water just above the fluid-fluid interface with a short laser pulse. The first growth-shrink cycle of the bubble lasts only 40 microseconds. During the shrinkage or so-called collapse of the bubble, a jet is formed and accelerated from the top of the bubble towards the heavier liquid HFE.

Image credit: APS Physics