Capillary rise in tubes with sharp grooves

Lei-Han TANG, Yu Tang

Research output: Contribution to journalArticlepeer-review

Abstract

Liquid in grooved capillaries, made by e.g. inserting a plate in a cylindrical tube, exhibits unusual spreading and flow properties. One example is capillary rise, where a long, upward tongue on top of the usual meniscus has been observed along the groove. We attribute the underlying mechanism to a thermodynamic instability against spreading for a (partial or complete wetting) liquid in a sharp groove whose opening angle α is less than a critical value αc = π- 2θ. The equilibrium shape of the tongue is determined analytically. The dynamics of liquid rising is studied in the viscous regime. When the diameter of the tube is smaller than the capillary length, the center part of the meniscus rises with time t following a t1/2-law, while the tongue is truncated at a height which grows following a t1/3-law. Sharp groove also facilitates release of gas bubbles trapped inside a capillary under the action of gravity.

Original languageEnglish
Pages (from-to)881-890
Number of pages10
JournalJournal de Physique II
Volume4
Issue number5
DOIs
Publication statusPublished - May 1994

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