Bursting of Dilute Emulsion-Based Liquid Sheets Driven by a Marangoni Effect

Clara Vernay,Christian Ligoure,Laurence Ramos

doi:10.1103/physrevlett.115.198302

Abstract

We study the destabilization mechanism of thin liquid sheets expanding in air and show that dilute oil-in-water emulsion-based sheets disintegrate through the nucleation and growth of holes that perforate the sheet. The velocity and thickness fields of the sheet outside the holes are not perturbed by holes, and hole opening follows the Taylor-Culick law. We find that a prehole, which widens and thins out the sheet with time, systematically precedes the hole nucleation. The growth dynamics of the prehole follows the law theoretically predicted for a liquid spreading on another liquid of higher surface tension due to Marangoni stresses. Classical Marangoni spreading experiments quantitatively corroborate our findings.

Highlights

We study the destabilization mechanism of thin liquid sheets expanding in air and show that dilute oil-in-water emulsion-based sheets disintegrate through the nucleation and growth of holes that perforate the sheet
The disintegration of a liquid sheet through the formation of holes that perforate the liquid film was first mentioned by Dombrowski et al in the 50’s [3], and have been later reported to occur in different types of complex fluids, including surfactant solutions [4], solid suspensions [5], surfactant-stabilized air bubbles [6], and dilute oil-in-water emulsions [7]
The occurrence of perforation events in a spray directly decreases the fraction of small drops issued from the spray [8] as illustrated in the case of dilute emulsions, which are prone to induce the bursting of liquid sheets [7]

Summary

Introduction

We study the destabilization mechanism of thin liquid sheets expanding in air and show that dilute oil-in-water emulsion-based sheets disintegrate through the nucleation and growth of holes that perforate the sheet. In this Letter, we investigate the perforation mechanisms of an emulsion-based free liquid sheet issued from a single-drop experiment; resulting from the impact of one drop of fluid onto a small target [12,13,14].

Results

Conclusion