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Turbulent-like dynamics of slow imbibition fronts
Stéphane Santucci
Laboratoire de Physique, ENS de Lyon.
Wed, Jun. 10th 2015, 11:00-12:15
SPEC Salle Itzykson, Bât.774, Orme des Merisiers

I will present an experimental study of the dynamics of a viscous fluid interface forced to invade a disordered medium at constant flow rate. 

A multi-scale analysis of the spatially averaged velocity Vl (t) of those imbibition fronts measured at scale l reveals that the slow front dynamics is intermittent: the distributions of the velocity increments ΔVl (τ) = Vl (t+ τ) - Vl (t) evolve continuously through time scales τ, from heavy-tailed to Gaussian—reached at a time lag τC, set by the extent of the medium heterogeneities. Intermittency results from capillary bursts triggered from the smallest scale of the disorder up to the scale lC at which viscous dissipation becomes dominant. The effective number of degrees of freedom of the front l = lC controls its intensity.


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