Nonlinear hydrodynamic effects induced by Rayleigh surface acoustic wave in sessile droplets

M. Alghane, Baixin Chen, Yong Qing Fu, Yifan Li, Marc Desmulliez, M. I. Mohammed, Anthony Walton

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

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/Rd) ≥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 Rd 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
Original languageEnglish
Pages (from-to)056304
JournalPhysical Review E
Volume86
Issue number5
DOIs
Publication statusPublished - 9 Nov 2012

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