Publications de François Gallaire

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We investigate the stability of thin viscous films coated on the inside of a horizontal cylindrical substrate. In such a case, gravity acts both as a stabilizing force through the progressive drainage of the film and as a destabilizing force prone to form ...

The present paper investigates numerically and theoretically the axisymmetric vortex breakdown occurring in a constricted pipe of infinite extension, i.e., the transition from a smooth columnar state to a breakdown state exhibiting a recirculation bubble. ...

A swirling wake flow submitted to an adverse pressure gradient is studied by bifurcation analysis, modal analysis and direct numerical simulations. In contrast to experiments in diverging tubes, the adverse pressure gradient is imposed by the presence of a ...

Prior modal stability analysis (Kojima et al., Phys. Fluids, vol. 27, 1984, pp. 19-32) predicted that a rising or sedimenting droplet in a viscous fluid is stable in the presence of surface tension no matter how small, in contrast to experimental and numer ...

The study and control of flow instabilities is a key problem in aerodynamics. Aircrafts are designed not only to generate the lift force needed to balance their weight but, more importantly, to be stable and reasonably steady when in cruise conditions. Sim ...

Inspired by recent experiments using synthetic microswimmers to manipulate droplets, we investigate the low-Reynolds-number locomotion of a model swimmer (a spherical squirmer) encapsulated inside a droplet of a comparable size in another viscous fluid. Me ...

We investigate the wake structure and the three-dimensional stability of the two-dimensional von Karman vortex street developing in the wake of a permeable circular cylinder. The flow through the porous medium, assumed homogenous and isotropic, is describe ...

A fluid droplet suspended in an extensional flow of moderate intensity may break into pieces, depending on the amplitude of the initial droplet deformation. In subcritical uniaxial extensional flow the nonbreaking base state is linearly stable, implying th ...

We analytically derive an amplitude equation for the weakly nonlinear evolution of the linearly most amplified response of a non-normal dynamical system. The development generalizes the method proposed in Ducimetière et al. (J. Fluid Mech., vol. 947, 2022, ...

A general formulation is proposed to control the integral amplification factor of harmonic disturbances in weakly non-parallel amplifier flows. The sensitivity of the local spatial stability spectrum to a base-flow modification is first determined, general ...

Beer tapping is a well known prank where a bottle of beer is impacted from the top by a solid object, usually another bottle, leading to a sudden foam overflow. A description of the shock-driven bubble dynamics leading to foaming is presented based on an e ...

We study microfluidic self-digitization in Hele-Shaw cells using pancake droplets anchored to surface-tension traps. We show that above a critical flow rate, large anchored droplets break up to form two daughter droplets, one of which remains in the anchor ...

To clarify the role of wetting properties on the damping of liquid oscillations, we studied the decay of oscillations of liquid columns in a U-shaped tube with controlled surface conditions. In the presence of sliding triple lines, oscillations are strongl ...

Archetypal falling behaviors of impervious objects are classified into four modes: fluttering, tumbling, steady descent, and chaotic motion. The classical scenario predicts these behaviors to be affected by three dimensionless quantities: thickness-to-widt ...

In this review article, we exemplify the use of stability analysis tools to rationalize pattern formation in complex media. Specifically, we focus on fluid flows, and show how the destabilization of their interface sets the blueprint of the patterns they e ...

The flow of a thin film coating the underside of an inclined substrate is studied. We measure experimentally spatial growth rates and compare them to the linear stability analysis of a flat film modelled by the lubrication equation. When forced by a statio ...

The supercritical instability leading to the Benard-von Karman vortex street in a cylinder wake is a well known example of supercritical Hopf bifurcation: the steady solution becomes linearly unstable and saturates into a periodic limit cycle. Nonetheless, ...

In two-phase microfluidics, droplets often undergo deformations that drive them away from their circular equilibrium shape. Herein we concentrate on the relaxation of symmetrical deformations to a circle driven by surface tension effects, which are predomi ...

This paper is associated with a video winner of a 2019 American Physical Society's Division of Fluid Dynamics (DFD) Gallery of Fluid Motion Award for work presented at the DFD Gallery of Fluid Motion. The original video is available online at the Gallery o ...

Tammisola et al (2012 J. Fluid Mech. 713 632-58) have observed a counter-intuitive destabilizing effect of the surface tension in planar wakes by means of a global linear analysis. In the present study, we conduct direct numerical simulation (DNS) of wakes ...

François Gallaire

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Rayleigh-Taylor instability under curved substrates: An optimal transient growth analysis

Control of axisymmetric vortex breakdown in a constricted pipe: Nonlinear steady states and weakly nonlinear asymptotic expansions

Vortex impingement onto an axisymmetric obstacle - subcritical bifurcation to vortex breakdown

The stability of a rising droplet: an inertialess non-modal growth mechanism

Flow dynamics of a dandelion pappus: A linear stability approach

Swimming with a cage: low-Reynolds-number locomotion inside a droplet

Von Karman vortex street past a permeable circular cylinder. Two-dimensional flow and dynamic-mode-decomposition-based secondary stability analysis

Edge states control droplet breakup in subcritical extensional flows

A weakly nonlinear amplitude equation approach to the bypass transition in the two-dimensional Lamb–Oseen vortex

Flow control of weakly non-parallel flows: application to trailing vortices

Beer tapping: dynamics of bubbles after impact

Breaking Anchored Droplets in a Microfluidic Hele-Shaw Cell

Transition from Exponentially Damped to Finite-Time Arrest Liquid Oscillations Induced by Contact Line Hysteresis

Tumbling elimination induced by permeability: An experimental approach

Fluid dynamic instabilities: theory and application to pattern forming in complex media

Instability of a thin viscous film flowing under an inclined substrate: steady patterns

A self-consistent model for the saturation dynamics of the vortex shedding around the mean flow in the unstable cylinder wake

Generic path for droplet relaxation in microfluidic channels

Swinging jets

Direct numerical simulations of two-phase immiscible wakes