Avalanches and Continuous Flow in Aging Aqueous Foam

TL;DR

This study employs coherent light scattering and introduces Temporal Contrast Analysis to distinguish and analyze avalanche-like and flow-like dynamics in aging aqueous foam, providing new insights into foam structural rearrangements.

Contribution

The paper presents a novel statistical tool, Temporal Contrast Analysis, to separately characterize and analyze different dynamical components in foam aging.

Findings

Detection of spontaneous avalanche-like events during foam aging

Identification of continuous flow-like rearrangements in foam structure

Quantitative analysis of decay of dynamical components over time

Abstract

We used coherent light scattering in a multi-speckle detection scheme to investigate the mesoscale dynamics in aqueous foam. Time-resolved correlation of the scattered speckle intensities reveals the details of foam dynamics during aging. We introduce Temporal Contrast Analysis, a novel statistical tool that can be effective in characterizing structural rearrangements. Using Temporal Contrast Analysis we were able to detect two distinct dynamical components present during foam aging: spontaneous and intermittent, avalanche-like events and continuous, flow-like rearrangements in the foam structure. We were able to measure these contributions separately from the intrinsic statistical noise contribution, and thereby independently analyze the decay of each dynamical component during foam aging process.