Damping sloshing waves using confinement, foams, or contact angle hysteresis

Par Benjamin Dollet, Chercheur CNRS, Laboratoire interdisciplinaire de Physique (LIPhy), UMR 5588 et Université Grenoble Alpes

Mardi 11 Juin,  14h00, Salle des séminaires (215), 2ème étage, Bâtiment A4N

Abstract :

Sloshing describes the oscillations of liquids in reservoirs. It is often detrimental: coffee spilling, safety of tankers and spacecrafts, hence understanding and optimising its damping is of primary importance for applications.

We first consider sloshing in a confined geometry. Experimentally, we study the motion of a liquid in a narrow rectangular cell shaken at different frequencies, and show that sloshing can then be suppressed for sufficiently viscous liquids. Theoretically, we present a slender-body model which enables to consider viscous dissipation at leading order, in excellent agreement with our measurements [Viola, Gallaire & Dollet, J. Fluid Mech. (2017)].

Second, we study sloshing in a cylindrical container of a liquid covered by a layer of foam. Foam damps sloshing efficiently, as beer drinkers know by experience. Moreover, due to the peculiar nature of foam/wall friction, we show that sloshing oscillations are damped in finite time, like solid friction, and unlike usual viscous dissipation [Viola, Brun, Dollet & Gallaire, Phys. Fluids (2016)].
Finally, for a liquid in partial wetting conditions, the role of triple line dynamics on damping has long been recognised, but has heretofore remained poorly understood. We show experimentally that contact line dynamics leads to strong effects: a less viscous liquid can display more damping than a more viscous one; and strong nonlinear responses, like a marked dependence on the initial amplitude, occur. We rationalise quantitatively all these observations by a hydrodynamic model with contact angle hysteresis as the key ingredient.

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