Sharp acceleration of a macroscopic contact line induced by a particle. (29th September 2017)

• Record Type: Journal Article
• Authors: Mu, Lizhong; Kondo, Daichi; Inoue, Motochika; Kaneko, Toshihiro; Yoshikawa, Harunori N.; Zoueshtiagh, Farzam; Ueno, Ichiro
• Is Part Of: Journal of fluid mechanics. Volume 830(2017)
• Publication Date: 2017-09-29
• Subjects: capillary flows, -- contact lines, -- drops; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2017.627
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : Wetting of a planar solid substrate is investigated in the presence of a macroscopic particle in the complete wetting regime. A drop of silicone oil spreads on the substrate and its macroscopic edge is incident on the particle at the late stage of spreading. The drop–particle interaction is observed in detail by shadowgraph and interferometry. Although the spreading drop edge is pinned by the particle for a short time, a sharp acceleration occurs when the liquid starts wetting the extra surface area offered by the particle and forming a meniscus. This process yields a net gain in spreading speed. A theoretical model based on the classical wetting dynamics dictated by Cox's law is developed. It predicts that the capillary energy of the meniscus gives rise to a rapid motion of the liquid edge, showing good agreement with the dynamics observed in the experiments.