Three-dimensional dynamics of falling films in the presence of insoluble surfactants

Abstract

We study the effect of insoluble surfactants on the wave dynamics of vertically-falling liquid films. We use three-dimensional numerical simulations and employ a hybrid interface-tracking/level-set method, taking into account Marangoni stresses induced by gradients of interfacial surfactant concentration. Our numerical predictions for the evolution of the surfactant-free, three-dimensional wave topology are validated against the experimental work of Park & Nosoko (2003). The addition of surfactants is found to influence significantly the development of horseshoe-shaped waves. At low Marangoni numbers, we show that the wave fronts exhibit spanwise oscillations before eventually acquiring a quasi two-dimensional shape. In addition, the presence of Marangoni stresses are found to suppress the peaks of the travelling waves and preceding capillary wave structures. At high Marangoni numbers, a near complete rigidification of the interface is observed.

arXiv comment10 pages, 5 figures

References in corpus (2)

• An Interface-Tracking Technique for Multiphase Flow with Soluble Surfactant
• Fluorescent visualization of a spreading surfactant

Cited by in corpus (5)

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• Direct numerical simulations of turbulent jets: vortex-interface-surfactant interactions
• Role of surfactant-induced Marangoni stresses in drop-interface coalescence
• Enhanced numerical approaches for modeling insoluble surfactants in two-phase flows with the diffuse-interface method