title: Foaming dynamics in Hele-Shaw cells.
abstract: We have studied foaming dynamics in Hele-Shaw cells partially filled with a soap and water mixture. A series of upside-down flips produces an intermittent wetting of the cell and leads to foam formation. As a function of the number of flips, an increasing number of bubbles composes the foam, until saturation is observed. Statistical analysis shows that the bubble size follows a Gamma distribution. Contrary to common belief, this foaming dynamics by "shaking" creates homogeneous foam, even though the system may pass through transient heterogeneous configurations. A mechanistic interpretation is proposed and included into a theoretical model.
authors.affiliation: GRASP, Institut de Physique B5, University of Liège, B-4000 Liège, Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Caps
authors.forename: N
authors.initials: N
authors.lastname: Vandewalle
authors.forename: G
authors.initials: G
authors.lastname: Broze