Experimental growth law for bubbles in a "wet" 3D liquid foam

TL;DR

This study uses X-ray tomography to analyze bubble growth in a wet 3D foam, revealing a linear relationship between average normalized growth rate and the number of bubble faces, providing new insights into foam dynamics.

Contribution

It introduces a quantitative growth law for bubbles in a wet foam, linking growth rate to the number of faces, based on extensive 3D imaging data.

Findings

Average growth rate scales linearly with the number of faces for large f

Growth rate dispersion is analyzed and discussed

Normalized growth rate depends on bubble volume and face number

Abstract

We used X-ray tomography to characterize the geometry of all bubbles in a liquid foam of average liquid fraction $\phi_l\approx 17 %$ and to follow their evolution, measuring the normalized growth rate $\mathcal{G}=V^{-{1/3}}\frac{dV} {dt}$ for 7000 bubbles. While $\mathcal{G}$ does not depend only on the number of faces of a bubble, its average over $f-$faced bubbles scales as $G_f\sim f-f_0$ for large $f$s at all times. We discuss the dispersion of $\mathcal{G}$ and the influence of $V$ on $\mathcal{G}$.