Modelling the wetting of a solid occlusion by a liquid film. (May 2015)

• Record Type: Journal Article
• Authors: Sellier, M.
• Is Part Of: International journal of multiphase flow. Volume 71(2015)
• Page Start: 66
• Page End: 73
• Publication Date: 2015-05
• Subjects: Thin liquid film -- Wetting -- Capillarity -- Film rupture; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2014.12.007
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: This paper investigates how the wetting front of a thin liquid film interacts with a protruding occlusion. This numerical investigation highlights conditions likely to lead to film rupture. The modelling is performed in the lubrication approximation framework. This paper establishes the existence of a critical substrate contact angle beyond which rupture occurs. This paper demonstrates that film rupture can be induced by a sharp corner in the occlusion. Abstract: We investigate in this work how the presence of an occlusion affects the dynamics of the wetting front of a liquid film draining down a vertical surface. This numerical study is developed in the context of the lubrication approximation. Through a parametric study, we show that depending on the asymptotic film thickness and the fluid properties, there exists a critical substrate contact angle below which separation of the contact line from the occlusion wall is observed which results in the appearance of a dry zone in the wake of the occlusion. In analogy with external aerodynamics, we also show that a sharp corner in the occlusion can induce this contact line separation. Our numerical results also highlight the importance of the occlusion wettability on the morphology of the wetting front suggesting a possible mechanism to control and mitigate the often undesirable fingering instability.