Agitation, Mixing, and Transfers Induced by Bubbles

Frédéric Risso (1)

1 IMFT - Institut de mécanique des fluides de Toulouse

Bubbly flows involve bubbles randomly distributed within a liquid. At large Reynolds number, they experience an agitation that can combine shear- induced turbulence (SIT), large-scale buoyancy-driven flows, and bubble- induced agitation (BIA). The properties of BIA strongly differ from those of SIT. They have been determined from studies of homogeneous swarms of rising bubbles. Regarding the bubbles, agitation is mainly caused by the wake-induced path instability. Regarding the liquid, two contributions must be distinguished. The first one corresponds to the anisotropic flow distur- bances generated near the bubbles, principally in the vertical direction. The second one is the almost isotropic turbulence induced by the flow instability through a population of bubbles, which turns out to be the main cause of horizontal fluctuations. Both contributions generate a k −3 spectral subrange and exponential probability density functions. The subsequent issue will be to understand how BIA interacts with SIT.

Mots clés: Bubbly flow; Dispersed two-phase flow; Bubbles; agitation; Turbulence

Domaines: Mécanique des fluides [physics.class-ph]

Frédéric Risso. Agitation, Mixing, and Transfers Induced by Bubbles. Annual Review of Fluid Mechanics, 2018, vol. 50, pp. 25-48. ⟨10.1146/annurev-fluid-122316-045003⟩. ⟨hal-01778999⟩