An experimental investigation of flow fields near a liquid-liquid moving contact line

Fuente: arXiv
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Hauptverfasser: Gupta, Charul, Chandrala, Lakshmana D, Dixit, Harish N
Format: Preprint
Veröffentlicht: 2024
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author Gupta, Charul
Chandrala, Lakshmana D
Dixit, Harish N
author_facet Gupta, Charul
Chandrala, Lakshmana D
Dixit, Harish N
contents 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, $λ$, and the dynamic contact angle, $θ_d$. 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.
format Preprint
id arxiv_https___arxiv_org_abs_2401_09347
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An experimental investigation of flow fields near a liquid-liquid moving contact line
Gupta, Charul
Chandrala, Lakshmana D
Dixit, Harish N
Fluid Dynamics
Soft Condensed Matter
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, $λ$, and the dynamic contact angle, $θ_d$. 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.
title An experimental investigation of flow fields near a liquid-liquid moving contact line
topic Fluid Dynamics
Soft Condensed Matter
url https://arxiv.org/abs/2401.09347