A new scaling number reveals droplet dynamics on vibratory surfaces

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

1 Scopus Citations
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Author(s)

  • Mingkai Song
  • Hongwei Zhao
  • Ting Wang
  • Shunbo Wang
  • Jie Wan

Related Research Unit(s)

Detail(s)

Original languageEnglish
Pages (from-to)2414-2420
Journal / PublicationJournal of Colloid and Interface Science
Volume608
Issue numberPart 3
Online published29 Oct 2021
Publication statusPublished - 15 Feb 2022

Abstract

Hypothesis: Droplet spreading on surfaces is a ubiquitous phenomenon in nature and is relevant with a wide range of applications. In practical scenarios, surfaces are usually associated with certain levels of vibration. Although vertical or horizontal modes of vibration have been used to promote droplet dewetting, bouncing from immiscible medium, directional transport, etc., a quantitative understanding of how external vibration mediates the droplet behaviors remains to be revealed.

Methods: We studied droplets impacting on stationary and vibratory surfaces, respectively. In analogy to the Weber number We = ρUi2D0/γ, we define the vibration Weber number We* = ρUv2D0/γ to quantitively analyze the vibration-induced dynamic pressure on droplet behaviors on vibratory surfaces, where ρ, γ, D0, Ui, and Uv are liquid density, surface tension, initial droplet diameter, impact velocity of the droplet, and velocity amplitude of vibration, respectively.

Findings: We demonstrate that the effect of vibration on promoting droplet spreading can be captured by a new scaling number expressed as We*/[We1 sin(θ/2)], leading to (DmDm0)/Dm0 ∝ We*/[We1 sin(θ/2)], where θ is the contact angle, and Dm0 and Dm are the maximum diameter of the droplet on stationary and vibratory surfaces, respectively. The scaling number illustrates the relative importance of vibration-induced dynamic pressure compared to inertial force and surface tension. Together with other well-established non-dimensional numbers, this scaling number provides a new dimension and framework for understanding and controlling droplet dynamics. Our findings can also find applications such as improving the power generation efficiency, intensifying the deposition of paint, and enhancing the heat transfer of droplets.

Research Area(s)

  • droplet spreading, vibratory surfaces, scaling relation, dynamic pressure

Citation Format(s)

A new scaling number reveals droplet dynamics on vibratory surfaces. / Song, Mingkai; Zhao, Hongwei; Wang, Ting; Wang, Shunbo; Wan, Jie; Qin, Xuezhi; Wang, Zuankai.

In: Journal of Colloid and Interface Science, Vol. 608, No. Part 3, 15.02.2022, p. 2414-2420.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review