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Updated: Apr 24, 2026

Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
Poloidal flow and toroidal particle ring formation in a sessile drop driven by megahertz order vibration
Amgad R Rezk1, Leslie Y Yeo, James R Friend
1Micro/Nanophysics Research Laboratory, Royal Melbourne Institute of Technology (RMIT) University , Melbourne, Victoria 3000, Australia.
Abstract:
Poloidal flow is curiously formed in a microliter sessile water drop over 157-225 MHz because of acoustic streaming from three-dimensional standing Lamb waves in a lithium niobate substrate. The flow possesses radial symmetry with downwelling at the center and upwelling around the periphery of the drop. Outside this frequency range, the attenuation occurs over a length scale incompatible with the drop size and the poloidal flow vanishes. Remarkably, shear-induced migration was found to drive toroidal particle ring formation with diameters inversely proportional to the frequency of the acoustic irradiation.
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