Rayleigh-Taylor-like instability in a foam film

Marginal regeneration-induced drainage of surface bubbles

“…Nevertheless, an accurate description of these buoyant patches and of their dynamics as well as a quantification of their contribution to the thinning dynamics is still lacking. In this paper, we visualize the patches, and show that their rising velocities and sizes are in good agreement with models respectively based on the balance of gravitational and surface viscous forces and on a Rayleigh-Taylor like instability [2,3]. Our results suggest that, in an environment saturated in humidity, the drainage induced by their dynamics correctly describes the film drainage at the apex of the bubble within the experimental error bars.…”

Local origin of the visco-elasticity of a millimetric elementary foam

“…However, gravity imposes a stratification of the non-horizontal films, and both Frankel films merge at the film bottom (Shabalina et al. 2019), thus explaining the film profile. The key point here is that the initial film is a well-identified material system, which does not leave or enter the film during the experiment, and which is well separated from the Frankel film by a measurable boundary.…”

Marginal regeneration in a horizontal film: Instability growth law in the nonlinear regime

“…The surface tension in the film is also modified by the line tension T ∼ 10 −10 N induced by the film thickness variation across the frontier between the thin and thick parts of the film, in a transition region of width δ ∼ 100 µm [20]. This line tension imposes a surface tension jump across the frontier, which is the 2D equivalent of the 3D Laplace pressure jump: in a patch of radius R, the tension is slightly smaller than in the thick film on the other side of the frontier, and the tension jump is T /R ∼ 10 −7 N/m.…”