Home

Archives







Rencontres Niçoises de Mécanique des Fluides

Année 2017


Fédération Wolfgang Döblin




Les Rencontres Niçoises de Mécanique des Fluides sont organisées par le Laboratoire J.A. Dieudonné (LJAD) de l'Université de Nice Sophia Antipolis, l'Observatoire de la Côte d'Azur (OCA), le Laboratoire de Physique de la Matière Condensée (LPMC) de Nice, l'Institut Non Linéaire de Nice (INLN) et le Centre de Mise En Forme de Matériaux (CEMEF).

Si vous voulez figurer sur la liste de diffusion, merci de nous contacter .


 

Lundi 11 Décembre 2017

Institut de Physique de Nice (ex LPMC)

salle Claude Brot

13h30


Nora Chérifa Abid (Institut Universitaire des Systèmes Thermiques Industriels, Université d’Aix-Marseille, France)



Thermoconvection, instabilités et transfert.

14h30


Henri Lhuissier (Institut Universitaire des Systèmes Thermiques Industriels, Université d’Aix-Marseille, France)



Suspension jets and drops.

15h30


Benjamin Dollet (Institut de Physique de Rennes, Université de Rennes, France)



Sloshing: damping with confinement or foams.






Nora Chérifa Abid (Institut Universitaire des Systèmes Thermiques Industriels, Université d’Aix-Marseille, France)



Thermoconvection, instabilités et transfert.



TBA



Henri Lhuissier (Institut Universitaire des Systèmes Thermiques Industriels, Université d’Aix-Marseille, France)



Suspension jets and drops.



Below a particle volume fraction of φc ∼ 60%, a suspension of large solid particles flows. Like any regular liquid, it can be shaped into jets or drops, but the formation and transient deformations of these small capillary objects is drastically modified by the presence of the particles. I will successively discuss two consequences of this granularity at the light of experiments with mono- disperse spherical particles. First, how adding particles to a liquid jet, despite increasing the jet effective viscosity, shortens the jet. Second, how a suspension drop, with particle volume fraction below or above φc deforms upon impact onto a solid plate and how the deformation depends on the particle size.



Benjamin Dollet (Institut de Physique de Rennes, Université de Rennes, France)



Sloshing: damping with confinement or foams.



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 air/liquid interface 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. On the theoretical side, while the classical analysis of sloshing determines inviscid modes and plugs in dissipation afterwards, which is not fully consistent, we present a slender-body approach which enables to consider viscous dissipation at leading order. The resullting predictions are 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, namely the fact that the friction force depends nonlinearly on the sliding exponent, with a power law of exponent lower than one, we show that sloshing oscillations are damped in finite time, like solid friction, and unlike usual viscous dissipation. We rationalise this observation using multiple-scale analysis [Viola, Brun, Dollet & Gallaire, Phys. Fluids (2016)].


powered by ESTIQUAATSI