Nonlinear hydrodynamic effects induced by Rayleigh surface acoustic wave in sessile droplets - Alghane et al 2012.pdf (981.33 kB)
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Nonlinear hydrodynamic effects induced by Rayleigh surface acoustic wave in sessile droplets

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journal contribution
posted on 10.07.2020, 15:10 by M Alghane, BX Chen, YQ Fu, Y Li, MPY Desmulliez, Mazher MohammedMazher Mohammed, AJ Walton
We report an experimental and numerical characterization of three-dimensional acoustic streaming behavior in small droplets of volumes (1-30 μl) induced by surface acoustic wave (SAW). We provide a quantitative evidence of the existence of strong nonlinear nature of the flow inertia in this SAW-driven flow over a range of the newly defined acoustic parameter F{NA}=Fλ/(σ/R_{d})≥0.01, which is a measure of the strength of the acoustic force to surface tension, where F is the acoustic body force, λ is the SAW wavelength, σ is the surface tension, and R{d} is the droplet radius. In contrast to the widely used Stokes model of acoustic streaming, which generally ignores such a nonlinearity, we identify that the full Navier-Stokes equation must be applied to avoid errors up to 93% between the computed streaming velocities and those from experiments as in the nonlinear case. We suggest that the Stokes model is valid only for very small acoustic power of ≤1 μW (F{NA}<0.002). Furthermore, we demonstrate that the increase of F{NA} above 0.45 induces not only internal streaming, but also the deformation of droplets.

Funding

Innovative electronic Manufacturing Research Center (IeMRC) through the EPSRC funded flagship project SMART MICROSYSTEMS (FS/01/02/10), the Carnegie Trust Funding, the Royal Society of London (Research Grant No. RG090609), and the Royal Society of Edinburgh.

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Published in

Physical Review E

Volume

86

Issue

5

Publisher

American Physical Society (APS)

Version

VoR (Version of Record)

Rights holder

© American Physical Society

Publisher statement

This paper was published in the journal Physical Review E and is available at https://doi.org/10.1103/PhysRevE.86.056304.

Publication date

2012-11-09

Copyright date

2012

ISSN

1539-3755

eISSN

1550-2376

Language

en

Depositor

Dr Mazher Mohammed. Deposit date: 8 July 2020

Article number

056304

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