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Experimental Characterization of Acoustic Streaming in Gradients of Density and Compressibility

Qiu, Wei LU ; Karlsen, Jonas T.; Bruus, Henrik and Augustsson, Per LU (2019) In Physical Review Applied 11(2).
Abstract

Suppression of boundary-driven Rayleigh streaming has recently been demonstrated for fluids of spatial inhomogeneity in density and compressibility owing to the competition between the boundary-layer-induced streaming stress and the inhomogeneity-induced acoustic body force. To understand the implications of this for acoustofluidic particle handling in the submicrometer regime, we here characterize acoustic streaming by general defocusing particle tracking inside a half-wavelength acoustic resonator filled with two miscible aqueous solutions of different density and speed of sound by adjusting the mass fraction of solute molecules. We follow the temporal evolution of the system as the solute molecules become homogenized by diffusion and... (More)

Suppression of boundary-driven Rayleigh streaming has recently been demonstrated for fluids of spatial inhomogeneity in density and compressibility owing to the competition between the boundary-layer-induced streaming stress and the inhomogeneity-induced acoustic body force. To understand the implications of this for acoustofluidic particle handling in the submicrometer regime, we here characterize acoustic streaming by general defocusing particle tracking inside a half-wavelength acoustic resonator filled with two miscible aqueous solutions of different density and speed of sound by adjusting the mass fraction of solute molecules. We follow the temporal evolution of the system as the solute molecules become homogenized by diffusion and advection. The acoustic streaming is suppressed in the bulk of the microchannel for 70-200 s, depending on the choice of inhomogeneous solutions. From confocal measurements of the concentration field of fluorescently labeled Ficoll solute molecules, we conclude that the temporal evolution of the acoustic streaming depends on the diffusivity and the initial distribution of these molecules. Suppression and deformation of the streaming rolls are observed for inhomogeneities in the solute mass fraction down to 0.1%.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review Applied
volume
11
issue
2
publisher
American Physical Society
external identifiers
  • scopus:85061246446
ISSN
2331-7019
DOI
10.1103/PhysRevApplied.11.024018
language
English
LU publication?
yes
id
f991c997-0632-4e1f-a8c7-df73b7db5485
date added to LUP
2019-02-19 08:29:29
date last changed
2019-03-19 04:05:35
@article{f991c997-0632-4e1f-a8c7-df73b7db5485,
  abstract     = {<p>Suppression of boundary-driven Rayleigh streaming has recently been demonstrated for fluids of spatial inhomogeneity in density and compressibility owing to the competition between the boundary-layer-induced streaming stress and the inhomogeneity-induced acoustic body force. To understand the implications of this for acoustofluidic particle handling in the submicrometer regime, we here characterize acoustic streaming by general defocusing particle tracking inside a half-wavelength acoustic resonator filled with two miscible aqueous solutions of different density and speed of sound by adjusting the mass fraction of solute molecules. We follow the temporal evolution of the system as the solute molecules become homogenized by diffusion and advection. The acoustic streaming is suppressed in the bulk of the microchannel for 70-200 s, depending on the choice of inhomogeneous solutions. From confocal measurements of the concentration field of fluorescently labeled Ficoll solute molecules, we conclude that the temporal evolution of the acoustic streaming depends on the diffusivity and the initial distribution of these molecules. Suppression and deformation of the streaming rolls are observed for inhomogeneities in the solute mass fraction down to 0.1%.</p>},
  articleno    = {024018},
  author       = {Qiu, Wei and Karlsen, Jonas T. and Bruus, Henrik and Augustsson, Per},
  issn         = {2331-7019},
  language     = {eng},
  month        = {02},
  number       = {2},
  publisher    = {American Physical Society},
  series       = {Physical Review Applied},
  title        = {Experimental Characterization of Acoustic Streaming in Gradients of Density and Compressibility},
  url          = {http://dx.doi.org/10.1103/PhysRevApplied.11.024018},
  volume       = {11},
  year         = {2019},
}