Publications de Pier Giuseppe Ledda

Instability and trajectories of buoyancy-driven annular disks: A numerical study

François Gallaire, Pier Giuseppe Ledda, Giovanni Vagnoli

We investigate the stability of the steady vertical path and the emerging trajectories of a buoyancy -driven annular disk as the diameter of its central hole is varied. The steady and axisymmetric wake associated with the steady vertical path of the disk, ...

Amer Physical Soc2024

Permeability sets the linear path instability of buoyancy-driven disks

François Gallaire, Pier Giuseppe Ledda, Giuseppe Antonio Zampogna, Giovanni Vagnoli

The prediction of trajectories of buoyancy-driven objects immersed in a viscous fluid is a key problem in fluid dynamics. Simple-shaped objects, such as disks, present a great variety of trajectories, ranging from zig-zag to tumbling and chaotic motions. Y ...

Cambridge University Press2023

Homogenization theory captures macroscopic flow discontinuities across Janus membranes

François Gallaire, Pier Giuseppe Ledda, Giuseppe Antonio Zampogna, Kevin Wittkowski

Janus membranes, thin permeable structures with chemical and geometrical asymmetric properties, show great potential in industrial separation processes. Yet the link between the micro- and macro-scale behaviours of these membranes needs to be established r ...

Cambridge University Press2023

From coating flow patterns to porous body wake dynamics via multiscale models

Pier Giuseppe Ledda

Multiscale phenomena are involved in countless problems in fluid mechanics. Coating flows are known to exhibit a broad variety of patterns, such as wine tears in a glass and dripping of fresh paint applied on a wall. Coating flows are typically modeled und ...

EPFL2022

Transport across thin membranes: Effective solute flux jump

François Gallaire, Pier Giuseppe Ledda, Giuseppe Antonio Zampogna

A model to describe the transport across membranes of chemical species dissolved in an incompressible flow is developed via homogenization. The asymptotic matching between the microscopic and macroscopic solute concentration fields leads to a solute flux j ...

AIP Publishing2022

Gravity-driven coatings on curved substrates: a differential geometry approach

François Gallaire, Pier Giuseppe Ledda

Drainage and spreading processes in thin liquid films have received considerable attention in the past decades. Yet, our understanding of three-dimensional cases remains sparse, with only a few studies focusing on flat and axisymmetric substrates. Here, we ...

Cambridge University Press2022

On the effect of a penetrating recirculation region on the bifurcations of the flow past a permeable sphere

François Gallaire, Pier Giuseppe Ledda, Giuseppe Antonio Zampogna, Matteo Ciuti

We study the flow past a permeable sphere modeled using homogenization theory. The flow through the porous medium is described by the Darcy law, in which the permeability quantifies the resistance for the fluid to pass through the microstructure. A slip co ...

AIP Publishing2021

Instability of a thin viscous film flowing under an inclined substrate: the emergence and stability of rivulets – CORRIGENDUM

François Gallaire, Gioele Mariano Nicolò Balestra, Pier Giuseppe Ledda, Gaëtan Pierre Clément Lerisson

Cambridge University Press2021

Hydrodynamic-driven morphogenesis of karst draperies: spatio-temporal analysis of the two-dimensional impulse response – CORRIGENDUM

François Gallaire, Matthieu Wyart, Gioele Mariano Nicolò Balestra, Pier Giuseppe Ledda, Gaëtan Pierre Clément Lerisson

Cambridge University Press2021

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

François Gallaire, Gioele Mariano Nicolò Balestra, Pier Giuseppe Ledda, Gaëtan Pierre Clément Lerisson

Cambridge University Press2021