https://doi.org/10.1140/epjs/s11734-024-01170-x
Regular Article
An experimental investigation of flow fields near a liquid–liquid moving contact line
1
Department of Mechanical & Aerospace Engineering, Indian Institute of Technology Hyderabad, Kandi, 502284, Sangareddy, Telangana, India
2
Centre for Interdisciplinary Programs, Indian Institute of Technology Hyderabad, Kandi, 502284, Sangareddy, Telangana, India
Received:
16
January
2024
Accepted:
12
April
2024
Published online:
26
April
2024
A moving contact line occurs at the intersection of an interface formed between two immiscible liquids and a solid. According to viscous theory, the flow is entirely governed by just two parameters, the viscosity ratio, 
, and the dynamic contact angle, 
. While a majority of experimental studies on moving contact lines involve determining the relationship between the dynamic contact angle and capillary number, a few studies have focused on measuring the flow field in the vicinity of the contact line involving liquid–gas interfaces. However, none of the studies have considered liquid–liquid moving contact lines and the present study fills this vital gap. Using particle image velocimetry, we simultaneously measure the velocity field in both the liquid phases using refractive index-matching techniques. The flow field obtained from experiments in both phases is directly compared against theoretical models. Measurement of interface speed reveals that material points rapidly slow down as the contact line is approached. Further, the experiments also reveal the presence of slip along the moving wall in the vicinity of the contact line suggesting a clear mechanism for how the singularity is arrested at the contact line.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
