Capillary jet in a slab of foam

Abstract

A capillary jet plunging into a quasi-2D slab of monodisperse foam of the same solution is studied experimentally. We show that the jet can have a drastic impact on the foam. At small speeds it inflates the channels separating the bubbles. At intermediate speeds, impact with channels creates very small bubbles. At higher speeds, the jet thins the foam films, which can result in bubble rupture. We study the mechanisms behind these processes using an elementary foam formed by three soap films in contact through a Plateau border. We obtain scaling laws, which transfer quantitatively from the elementary foam to the 2D foam.