Local effects of gravity on foams

Davis, M.J., Stewart, P. and Davis, S. (2013) Local effects of gravity on foams. Journal of Fluid Mechanics, 737, pp. 1-18. (doi:10.1017/jfm.2013.433)

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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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stewart, Dr Peter
Authors: Davis, M.J., Stewart, P., and Davis, S.
College/School:College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Journal of Fluid Mechanics
Publisher:Cambridge University Press
ISSN:0022-1120
ISSN (Online):1469-7645

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