Interfacial bubbles formed by plunging thin liquid films in a pool

Louis Salkin (1) , Alexandre Schmit (1) , Richard David (1) , Alexandre Delvert (1) , Eric Gicquel (1) , Pascal Panizza (1) , Laurent Courbin (1)

1 IPR - Institut de Physique de Rennes

We show that the immersion of an horizontally-suspended thin film of liquid in a pool of the same fluid creates an interfacial bubble, that is, a bubble at the liquid-air interface. Varying the fluid properties, the film's size and its immersion velocity, our experiments unveil two formation regimes characterized by either a visco-capillary or an inertio-capillary mechanism that controls the size of a produced bubble. To rationalize these results, we compare the pressure exerted by the air flow under a plunging film with the Laplace pressure needed to generate film dimpling, which subsequently yields air entrapment and the production of a bubble. This physical model explains the power-law variations of the bubble size with the governing dimensionless number for each regime.

Keywords: air entrainment; solid-surface; soap films; entrapment; mechanism; sphere

Keywords: drop impact; dynamics

Domains: Physics [physics]

Louis Salkin, Alexandre Schmit, Richard David, Alexandre Delvert, Eric Gicquel, et al.. Interfacial bubbles formed by plunging thin liquid films in a pool. Physical Review Fluids, 2017, 2 (6), pp.063604. ⟨10.1103/PhysRevFluids.2.063604⟩. ⟨hal-01548219⟩