Journal article
Ultrasound rays in droplets: The role of viscosity and caustics in acoustic streaming
When an acoustic wave propagates through a viscous fluid, it progressively transfers momentum to the fluid through viscous dissipation, which results in the formation of a steady vortical flow called acoustic streaming. Although spawned by viscous effects, the magnitude of the streaming does not depend on the viscosity in most simple geometries.
However, viscosity has a profound influence on the acoustic streaming as demonstrated by Riaud et al. (J. Fluid Mech., vol. 821, 2017, pp. 384-420) in their study of sessile mm-sized water-glycerol droplets placed on a piezoelectric substrate with a 20-MHz ultrasound surface acoustic wave propagating along its surface.
A detailed experimental and numerical analysis reveals that streaming dynamics is driven by a few ultrasound ray caustics inside the droplet.
Language: | English |
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Publisher: | Cambridge University Press |
Year: | 2017 |
Pages: | 1-4 |
ISSN: | 14697645 and 00221120 |
Types: | Journal article |
DOI: | 10.1017/jfm.2017.420 |
ORCIDs: | Bruus, Henrik |