Partial coalescence of soap bubbles

A soap bubble coalesces with a soap film, executing a coalescence cascade related to that arising when a water drop coalesces in a water bath.

We present the results of an experimental investigation of the merger of a soap bubble with a planar soap film. When gently deposited onto a horizontal film, a bubble may interact with the underlying film in such a way as to decrease in size, leaving behind a smaller daughter bubble with approximately half the radius of its progenitor. The process repeats up to three times, with each partial coalescence event occurring over a time scale comparable to the inertial-capillary time. Our results are compared to the recent numerical simulations of Martin and Blanchette (2015) and to the coalescence cascade of droplets on a fluid bath.

See paper here:  Pucci, Harris & Bush (2015)
See related Gallery of Fluid Motion winner here:  Pucci, Harris & Bush (2016)