Contact Line Pinning and Depinning Can Modulate the Rod-Climbing Effect

Chandra, NK and Ghosh, UU and Saha, A and Kumar, A (2021) Contact Line Pinning and Depinning Can Modulate the Rod-Climbing Effect. In: Langmuir .

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Abstract

Our experiments on the rod-climbing effect with an oil-coated rod revealed two key differences in the rod-climbing phenomena compared to a bare rod. First, an enhancement in the magnitude of climbing height for any particular value of the rod rotational speed and second, a decrease in the threshold rod rotational speed required for the appearance of the rod-climbing effect were observed. Observed phenomena are explained by considering the contact line behavior at the rod-fluid interface. Transient evolution of the meniscus at the rod-fluid interface revealed that the three-phase contact line was pinned for a bare rod and depinned for an oil-coated rod. We modeled the subject fluid as a Giesekus fluid to predict the climbing height. The differences in the contact line behavior were incorporated via the contact angle at the rod-fluid interface as a boundary condition. Agreement was found between the observed and predicted climbing height, establishing that contact line behavior may modulate the rod-climbing effect. ©

Item Type:	Journal Article
Publication:	Langmuir
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society
Keywords:	Fluidity; Magnetic bubbles, Contact line pinning; Contact lines; Depinning; Fluid interface; Giesekus fluids; Rod-climbing effects; Rotational speed; Three-phase contact line; Transient evolution, Contact angle
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	13 Dec 2021 11:33
Last Modified:	13 Dec 2021 11:33
URI:	http://eprints.iisc.ac.in/id/eprint/70737

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