Drastic changes in interfacial hydrodynamics due to wall slippage: Slip-intensified film thinning, drop spreading, and capillary instability

Ying Chih Liao, Yen Ching Li, Hsien Hung Wei

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

We report that wall slippage can drastically change both steady and dynamic flow characteristics for a wide class of free-surface thin film flows. This is demonstrated by (i) the breakdown of the 2/3 law and its replacement by a new quadratic law for the deposited film thickness in the Landau-Levich-Bretherton coating, (ii) the departure from de Gennes-Tanner's cubic law for dynamic contact angles in drop spreading, consequently resulting in much faster spreading than the classical Tanner law, and (iii) the exaggerated capillary instability of an annular film where a fractional amount of wall slip can lead to much more rapid draining and hence make the film more vulnerable to rupture. In (ii), the molecular precursor film is shown to have a length varying like the -1/2 power of the spreading speed, producing an anomalous 1/3 diffusion law governing its spreading dynamics. A variety of existing experimental findings can be well captured by the new scaling laws we derive. All these features are accompanied with no-slip-to-slip transitions, offering alternative means for probing slip boundaries.

Original languageEnglish
Article number136001
JournalPhysical review letters
Volume111
Issue number13
DOIs
Publication statusPublished - 2013 Sep 26

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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