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Mean flow generation in orbital sloshing


J. Bouvard, W. Herreman, F. Moisy


It is common knowledge that prescribing an orbital motion to a glass of wine generates a rotating gravity wave that comes along with a swirling mean flow. This mean flow rotates in the direction of the wave and recirculates poloidaly (radially and vertically), thus permanently pushing new fluid to the surface where it aerates and releases the wine's aromas.


Swirling a glass of wine generates a rotating wave which, in turn, generates a rotating mean flow with poloidal (radial and vertical) recirculation. Movie taken from winefolly.com (see also the Oenodynamic project from EPFL).



Precisely the same kind of orbital shaking is used on a more professional level in bioreactors for the cultivation of biological cells. There, the presence of the mean flow prevents sedimentation and ensures efficient gas exchange, avoiding the damagingly high shear rates that immersed stirrers would cause.


Mean flow, measured by stroboscopic PIV, showing the strong axial rotation (left) and the weaker poloidal recirculation vortices (right).



In order to decipher the origin of this mean flow induced by a swirling wave, we have performed experiments using silicon oil (a fluid more viscous than wine - don't drink it), orbitally shaken in a cylinder. We use stroboscopic Particle Image Velocimetry synchronized with the forcing frequency to measure the (Lagrangian) mean flow.

The mean flow is composed of a strong axial rotation and weaker recirculation vortices, mostly active near the contact line. Analysis suggests that the axial rotation is dominated by the Stokes drift (a kinematic mass transport mechanism in non-homogeneous wave fields), whereas the poloidal recirculations are essentially driven by the dynamics of the oscillating boundary layers (streaming flow).

Now, what if you swirl a glass of beer? This is another story...


Publication

  • Mean mass transport in an orbitally shaken cylindrical container
    J. Bouvard, W. Herreman and F. Moisy, Phys. Rev. Fluids 2, 084801 (2017)
    [Abstract | PDF]

Last modification: August 09 2017, 18:00:58.