A tentative geometrical description of static dilatancy in liquid foams: ordered 2D and 3D foams

TL;DR

This paper offers a geometrical interpretation of static dilatancy in liquid foams, explaining how deformation affects liquid content in 2D and 3D foam structures, with implications for understanding foam mechanics.

Contribution

It introduces a geometrical model for static dilatancy in liquid foams, distinguishing between ideal 2D and real dry foam behaviors, and clarifies the conditions under which negative dilatancy occurs.

Findings

Negative dilatancy predicted for ideal 2D foams at low liquid fractions.

Experimental evidence shows dynamic dilatancy depends on deformation rate.

The model suggests negative dilatancy is not observed in dry real 2D foams.

Abstract

Liquid foams have been observed to behave like immersed granular materials in at least one respect: deformation tends to raise their liquid contents, a phenomenon called dilatancy. We present a geometrical interpretation thereof in foams squeezed between two solid plates (2D GG foams), which contain pseudo Plateau borders along the plates, and in 3D foams. While experimental observations evidenced the effect of a continuous deformation rate (dynamic dilatancy), the present argument applies primarily to elastic deformation (static dilatancy). We show that the negative dilatancy predicted by Weaire and Hutzler (Phil. Mag. 83 (2003) 2747) at very low liquid fractions is specific to ideal 2D foams and should not be observed in the dry limit of real 2D foams.