Non-diffusive folding between silicone oils Thread viscosity = 500 cP Surroundings viscosity = 6 cP Acquisition rate: 1,600 fps |
The
flow morphologies exhibit periodic oscillations depending upon the flow
rates. In the diverging channel, the folds increase in amplitude, the
wavelength decreases, and the thread thins. The peak folding amplitude
defines an envelope between the less viscous liquid and the more
viscous folded central region. [T. Cubaud and T.G. Mason, Phys. Rev. Lett., 96, 114501 (2006)] |
The
interplay between folding
and the high viscosity gradient leads to the formation of heterogeneous
viscous mixtures downstream. In this case, the heterogeneous deposition
of the thread creates a pile having nonperiodic viscous ripples. As
opposed to purely diffusive flows, viscous folding offers the practical
ability to rapidly enhance mixing between liquids having different
viscosities in microfluidic devices. [T. Cubaud and T.G. Mason, Phys. Rev. Lett., 96, 114501 (2006)] |
Heterogeneous folding Thread viscosity = 500 cP Surroundings viscosity = 0.5 cP Acquisition rate: 1,600 fps |
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