Release Time:2019-03-11  Hits:

Indexed by: Journal Article

Date of Publication: 2017-11-01

Journal: JOURNAL OF FLUID MECHANICS

Included Journals: EI、SCIE、Scopus

Volume: 830

ISSN: 0022-1120

Key Words: capillary flows; contact lines; drops

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.