Alexandre Cohen
University of Nice Sophia Antipolis
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Publication
Featured researches published by Alexandre Cohen.
Physics of Fluids | 2014
Franck Celestini; Thomas Frisch; Alexandre Cohen; Christophe Raufaste; Laurent Duchemin; Yves Pomeau
We experimentally and theoretically investigate the behavior of Leidenfrost droplets inserted in a Hele-Shaw cell. As a result of the confinement from the two surfaces, the droplet has the shape of a flattened disc and is thermally isolated from the surface by the two evaporating vapor layers. An analysis of the evaporation rate using simple scaling arguments is in agreement with the experimental results. Using the lubrication approximation we numerically determine the shape of the droplets as a function of its radius. We furthermore find that the droplet width tends to zero at its center when the radius reaches a critical value. This prediction is corroborated experimentally by the direct observation of the sudden transition from a flattened disc into an expending torus. Below this critical size, the droplets are also displaying capillary azimuthal oscillating modes reminiscent of a hydrodynamic instability.
Physical Review Letters | 2017
Alexandre Cohen; Nathalie Fraysse; Christophe Raufaste
We subject a single Plateau border channel to a transverse harmonic excitation, in an experiment reminiscent of the historical one by Melde on vibrating strings, to study foam stability and wave properties. At low driving amplitudes, the liquid string exhibits regular oscillations. At large ones, a nonlinear regime appears and the acoustic radiation splits the channel into two zones of different cross section area, vibration amplitude, and phase difference with the neighboring soap films. The channel experiences an inertial dilatancy that is accounted for by a new Bernoulli-like relation.
Physical Review Letters | 2014
Alexandre Cohen; Nathalie Fraysse; Jean Rajchenbach; Médéric Argentina; Yann Bouret; Christophe Raufaste
Bulletin of the American Physical Society | 2017
Christophe Raufaste; Alexandre Cohen; Nathalie Fraysse; Jean Rajchenbach; Yann Bouret; Médéric Argentina
Physical Review Fluids | 2016
Yann Bouret; Alexandre Cohen; Nathalie Fraysse; Médéric Argentina; Christophe Raufaste
Physical Review E | 2015
Alexandre Cohen; Nathalie Fraysse; Christophe Raufaste
Journal of Fluid Mechanics | 2015
Médéric Argentina; Alexandre Cohen; Yann Bouret; Nathalie Fraysse; Christophe Raufaste
Archive | 2014
Alexandre Cohen; Nathalie Fraysse; Jean Rajchenbach; Médéric Argentina; Yann Bouret; Christophe Raufaste
eufoam2014 | 2013
Alexandre Cohen; Nathalie Fraysse; Jean Rajchenbach; Médéric Argentina; Yann Bouret; Christophe Raufaste
Réunion annuelle du GdR M&Em (Mousses et Emulsions) | 2013
Alexandre Cohen; Nathalie Fraysse; Jean Rajchenbach; Christophe Raufaste