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François Gallaire

Cette personne a quitté l’EPFL

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Publications associées (151)

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A pancake droplet translating in a Hele-Shaw cell: lubrication film and flow field

François Gallaire, Lailai Zhu

We adopt a boundary integral method to study the dynamics of a translating droplet confined in a Hele-Shaw cell in the Stokes regime. The droplet is driven by the motion of the ambient fluid with the same viscosity. We characterize the three-dimensional (3 ...

Cambridge University Press2016

A new prediction of wavelength selection in radial viscous fingering involving normal and tangential stresses

François Gallaire, Mathias Nagel

We reconsider the radial Saffman-Taylor instability when a fluid injected from a point source displaces another fluid of higher viscosity in a Hele-Shaw cell where the fluids are confined between two neighboring flat plates. The advancing fluid front is un ...

2013

Viscous Taylor droplets in axisymmetric and planar tubes: from Bretherton’s theory to empirical models

François Gallaire, Gioele Mariano Nicolò Balestra, Lailai Zhu

The aim of this study is to derive accurate models for quantities characterizing the dynamics of droplets of non-vanishing viscosity in capillaries. In particular, we propose models for the uniform-film thickness separating the droplet from the tube walls, ...

2018

Weakly nonlinear evolution of stochastically driven non-normal systems

François Gallaire, Edouard Boujo, Yves-Marie François Ducimetière

We consider nonlinear dynamical systems driven by stochastic forcing. It has been largely evidenced in the literature that the linear response of non-normal systems (e.g. fluid flows) may exhibit a large variance amplification, even in a linearly stable re ...

Cambridge University Press2022

Rayleigh-Taylor instability under a spherical substrate

François Gallaire, Gioele Mariano Nicolò Balestra

We investigate the Rayleigh-Taylor instability of a thin viscous film coating the inside of a spherical substrate. The aim of this work is to find and characterize the instability pattern in this spherical geometry. In contrast to the Rayleigh-Taylor insta ...

2018

Transport of flexible fibers in confined microchannels

François Gallaire, Mathias Simon Daniel Bechert

When transported in confined geometries rigid fibers show interesting transport dynamics induced by friction with the top and bottom walls. Fiber flexibility causes an additional coupling between fiber deformation and transport and is expected to lead to m ...

2019

Mode selection in trailing vortices: harmonic response of the non-parallel Batchelor vortex

François Gallaire, Francesco Viola

In the present study, the response of model trailing vortices subjected to a harmonic forcing is studied. To this purpose, a globally stable non-parallel Batchelor vortex is considered as the baseflow. Direct numerical simulations (DNS) show that a large v ...

Cambridge University Press2016

Impact of rotating and fixed nozzles on vortex breakdown in compressible swirling jet flows

François Gallaire

Vortex breakdown of swirling, round jet flows is investigated in the compressible, subsonic regime by means of Direct Numerical Simulation (DNS). This is achieved by solving the compressible Navier-Stokes equations on a cylindrical grid using high-order sp ...

Elsevier2016

Liquid film instability of an internally coated horizontal tube

François Gallaire, Edouard Boujo, Yves-Marie François Ducimetière, Shahab Eghbali

We study numerically and theoretically the gravity-driven flow of a viscous liquid film coating the inner side of a horizontal cylindrical tube and surrounding a shear-free dynamically inert gaseous core. The liquid-gas interface is prone to the Rayleigh-P ...

AMER PHYSICAL SOC2023

Marangoni induced force on a drop in a Hele Shaw cell

François Gallaire, Philippe Meliga

We analyse the force balance on a cylindrical drop in a Hele-Shaw cell, subjected to a Marangoni flow caused by a surface tension gradient. Depth-averaged Stokes equations, called Brinkman equations, are introduced and a general closed form solution is obt ...

American Institute of Physics2014

Nonlinear evolution of the centrifugal instability using a semilinear model

François Gallaire, Eunok Yim

We study the nonlinear evolution of the axisymmetric centrifugal instability developing on a columnar anticyclone with a Gaussian angular velocity using a semilinear approach. The model consists of two coupled equations: one for the linear evolution of the ...

Cambridge University Press2020

Inertial manipulation of bubbles in rectangular microfluidic channels

Demetri Psaltis, François Gallaire, Miguel Antonio Modestino, Gioele Mariano Nicolò Balestra, Seyyed Mohammad Hosseini Hashemi, Lailai Zhu, Pooria Hadikhani

Inertial microfluidics is an active field of research that deals with crossflow positioning of the suspended entities in microflows. Until now, the majority of the studies have focused on the behavior of rigid particles in order to provide guidelines for m ...

2018

Origin and role of the cerebrospinal fluid bidirectional flow in the central canal

François Gallaire, Ludovic Pierre Gustave Keiser

Circulation of the cerebrospinal fluid (CSF) contributes to body axis formation and brain development. Here, we investigated the unexplained origins of the CSF flow bidirectionality in the central canal of the spinal cord of 30 hpf zebrafish embryos and it ...

2020

Predictive control of spiral vortex breakdown

François Avellan, François Gallaire, Simon Pasche

The predictive control of the self-sustained single spiral vortex breakdown mode is addressed in the three-dimensional flow geometry of Ruith et al. (2003) for a constant swirl number S = 1.095. Based on adjoint optimization algorithms, two different contr ...

Cambridge University Press2018

Hub vortex instability within wind turbine wakes: Effects of wind turbulence, loading conditions, and blade aerodynamics

François Gallaire, Giacomo Valerio Iungo, Francesco Viola

The near wake of wind turbines is characterized by the presence of the hub vortex, which is a coherent vorticity structure generated from the interaction between the root vortices and the boundary layer evolving over the turbine nacelle. Bymoving downstrea ...

Amer Physical Soc2016

Quantitative analysis of the dripping and jetting regimes in co-flowing capillary jets

François Gallaire

We study a liquid jet that breaks up into drops in an external co-flowing liquid inside a confining microfluidic geometry. The jet breakup can occur right after the nozzle in a phenomenon named dripping or through the generation of a liquid jet that breaks ...

2011

Buoyancy-driven convection of droplets on hot nonwetting surfaces

François Gallaire, Eunok Yim

The global linear stability of a water drop on hot nonwetting surfaces is studied. The droplet is assumed to have a static shape and the surface tension gradient is neglected. First, the nonlinear steady Boussinesq equation is solved to obtain the axisymme ...

AMER PHYSICAL SOC2021

Controlled reattachment in separated flows: a variational approach to recirculation length reduction

François Gallaire, Edouard Boujo

A variational technique is used to derive analytical expressions for the sensitivity of recirculation length to steady forcing in separated flows. Linear sensitivity analysis is applied to the two-dimensional steady flow past a circular cylinder for Reynol ...

Cambridge University Press2014

A self-consistent formulation for the sensitivity analysis of finite-amplitude vortex shedding in the cylinder wake

François Gallaire, Edouard Boujo, Philippe Meliga

We use the adjoint method to compute sensitivity maps for the limit-cycle frequency and amplitude of the Benard von Karmzin vortex street in the wake of a circular cylinder. rfhe sensitivity, analysis is performed in the frame of the semi-linear self consi ...

Cambridge University Press2016

Breaking one into three: Surface-tension-driven droplet breakup in T-junctions

Philippe Renaud, François Gallaire, Arnaud Bertsch, Daniel Migliozzi, Yves-Marie François Ducimetière, Jiande Zhou, Ludovic Pierre Gustave Keiser

Droplet breakup is an important phenomenon in the field of microfluidics to generate daughter droplets. In this work, a novel breakup regime in the widely studied T-junction geometry is reported, where the pinch-off occurs laterally in the two outlet chann ...

AMER PHYSICAL SOC2023