Rapid Plateau border size variations expected in three simple experiments on 2D liquid foams.

Area of Science:

• Physics
• Materials Science
• Fluid Dynamics

Background:

• Foam geometry under confinement is complex, influenced by liquid fraction and squeezing.
• Two primary regimes exist: dry floor tiles and dry pancakes, defined by Plateau border radius relative to plate separation.

Purpose of the Study:

• To describe the geometry of 2D confined foams (2D GG foams) under varying conditions.
• To predict the behavior of Plateau border radius in different asymptotic regimes.
• To provide insights for experimental design in 2D GG foam studies.

Main Methods:

• Analysis of foam geometry in two asymptotic regimes: dry floor tiles and dry pancakes.
• Development of asymptotic predictions for foam behavior under drying, wetting, squeezing, stretching, and coarsening.
• Consideration of equilibrium configurations with negligible gravity and viscous flow effects.

Main Results:

• Identified two key parameters: liquid volume fraction and degree of squeezing.
• Predicted a rapid, non-topological variation in Plateau border radius within a specific part of the pancake regime.
• Offered asymptotic predictions for various experimental scenarios, including foam drying/wetting and coarsening.

Conclusions:

• The study predicts sudden appearances or disappearances of large Plateau borders in experiments with small inter-plate gaps.
• The findings provide expected orders of magnitude useful for designing experiments on 2D GG foams.
• While not a direct measurement method, the work highlights observable phenomena in confined foam systems.