Contact line pinning and de-pinning can modulate the rod-climbing effect
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. On one hand, an enhancement in magnitude of climbing height for any particular value of rod rotation speed and second, a decrease in threshold rod rotation speed required for the appearance of the rod-climbing effect were observed. Observed phenomena is explained by considering the contact line behavior at the rod-fluid interface. Transient evolution of meniscus at the rod-fluid interface revealed that the three-phase contact line was pinned for a bare rod and de-pinned for an oil-coated rod. We modelled the subject fluid as a Giesekus fluid to predict the climbing height. The differences in the contact line behaviour were incorporated via the contact angle at the rod-fluid interface as a boundary condition. An agreement was found between the observed and predicted climbing height establishing that contact line behaviour may modulate rod-climbing effect.
Keywords
Cite
@article{arxiv.2107.05184,
title = {Contact line pinning and de-pinning can modulate the rod-climbing effect},
author = {Navin Kumar Chandra and Udita. U. Ghosh and Aniruddha Saha and Aloke Kumar},
journal= {arXiv preprint arXiv:2107.05184},
year = {2021}
}