Liquid films with high surface modulus moving in tubes: dynamic wetting film and jumpy motion

TL;DR

This study examines the dynamics of high surface modulus soap films in tubes, revealing a distinct wetting zone affected by lamella motion and identifying a jumpy unsteady movement mode.

Contribution

It introduces detailed measurements of the dynamic wetting film and distinguishes surfactant models based on influence length dependence, also discovering a novel jumpy motion mode.

Findings

Identification of a dynamic wetting film zone influenced by lamella velocity

Dependence of influence length on lamella velocity and film thickness

Observation of a jumpy, unsteady lamella motion mode

Abstract

We investigate the motion through a wet tube of transverse soap films, or lamellae, of high surface dilatationnal modulus. Combining local thickness and velocity measurements in the wetting film, we reveal a zone of several centimeters in length, the dynamic wetting film, which is significantly influenced by a moving lamella. The dependence of this influence length on lamella velocity and wetting film thickness provides a discrimination among several possible surfactant minimal models. A spectacular jumpy mode of unsteady motion of a lamella is also evidenced.