Local effects of gravity on foams

Michael J. Davis*, Peter S. Stewart, Stephen H Davis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The stability of a two-dimensional surfactant-free (gas-liquid) foam in a gravitational field is considered. The foam is assumed to have low liquid fraction, so the gas phase can be divided into approximately polygonal bubbles separated by thin liquid films. These free films drain toward accumulations of liquid at the bubble vertices, the Plateau borders, and eventually rupture due to van der Waals intermolecular attractions; this drives foam coarsening through the coalescence of neighbouring bubbles. In particular, we demonstrate how gravitational effects strongly modify the shape of the Plateau border interfaces and enhance the drainage flow in the liquid films, driving non-uniform thinning with exponential decay of the minimum film thickness, significantly faster than the power-law thinning predicted when gravitational effects are negligible.

Original languageEnglish (US)
Pages (from-to)1-18
Number of pages18
JournalJournal of Fluid Mechanics
Volume737
DOIs
StatePublished - Dec 25 2013

Keywords

  • foams
  • interfacial flows (free surface)
  • thin films

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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