L’équipe appartient au réseau européen particle-based-cloud-modelling, et participe au projet IDEXLyon Breakthrough "Turbullet", qui réunit 6 laboratoires Lyonnais (physique, mécanique, mathématique, astro et géophysique).
Les approches concernant le mélange et la dispersion étant multiples, nous choisissons de nous concentrer sur des questions précises allant du point de vue lagrangien fondamental à la dispersion de particules réelles, éventuellement des bulles, des gouttelettes, ou plus généralement des écoulements diphasiques. On notera également des travaux récents sur les particules actives (en écoulements laminaires ou turbulents).
Voici par exemple deux questions auxquelles nous tentons de répondre :
particules anisotropes :
nous étudions des objets de géométrie sphéroïdale, dans la continuité de nos travaux. L’originalité de l’approche réside dans la prise en compte des corrections inertielles (dues à l’inertie du fluide) dans les équations du mouvement de translation et de rotation des objets.
L’étude a pour objectif l’application à la microphysique des nuages, les particules sphéroïdales modélisant des cristaux de glace.
Effet de la turbulence sur la sédimentation de particules sphériques de petite taille :
Contrairement à la vaste majorité des travaux récents sur le sujet, nous considérerons des objets dont le rapport de densité avec celui du fluide porteur est modéré. Des équations du mouvement plus élaborées, contenant notamment les forces de masse ajoutée et d’histoire, seront utilisées dans ce but.
Quelques publications associées à nos récents travaux :
2019
 Article dans New Journal of Physics (2019) Effect of fluid inertia on the orientation of a small prolate spheroid settling in turbulenceKristian Gustavsson, Muhammad Zubair Sheikh, Diego Lopez, Aurore Naso, Alain Pumir and Bernard Mehlig
We study the angular dynamics of small non-spherical particles settling in a turbulent flow, such as ice crystals in clouds, aggregates of organic material in the oceans, or fibres settling in (...) |
2018
 Article dans Comput. Fluids (2018) An improved multiscale Eulerian–Lagrangian method for simulation of atomization processDavide Zuzio, Jean-Luc Estivalèzes & Bastien Di Pierro
The physics of atomization process involve many spatial scales, generating a wide variety of liquid inclusions of different sizes with large density and viscosity ratios between liquid and gas (...) |
 Article dans J. Fluid Mech. (2018) The effective diffusivity of ordered and freely evolving bubbly suspensionsAurore Loisy, Aurore Naso & Peter D. M. Spelt
We investigate the dispersion of a passive scalar such as the concentration of a chemical species, or temperature, in homogeneous bubbly suspensions, by determining an effective diffusivity (...) |
 Article dans J. Fluid Mech. (2018) Collision rate of ice crystals with water droplets in turbulent flowsAurore Naso, Jennifer Jucha, Emmanuel Lévêque & Alain Pumir
Riming, the process whereby ice crystals get coated by impacting supercooled liquid droplets, is one of the dominant processes leading to precipitation in mixed-phase clouds. How a settling (...) |
 Article dans J. Fluid Mech. (2018) A note on Stokes’ problem in dense granular media using the $\mu(I)$-rheologyJ. John Soundar Jerome & Bastien Di Pierro
The classical Stokes’ problem describing the fluid motion due to a steadily moving infinite wall is revisited in the context of dense granular flows of mono-dispersed beads using the recently (...) |
 Article dans Int. J. Multiph. Flow (2018) Numerical analysis of the flapping mechanism for a two-phase coaxial jetNicolas Odier, Guillaume Balarac & Christophe Corre
A numerical study of a coaxial liquid jet sheared by an annular high-speed stream is performed at moderate density and velocity ratio between phases. The destabilization mechanism of the jet is (...) |
 Article dans Eur. J. Mech. B-Fluids (2018) A flow-pattern map for phase separation using the Navier–Stokes–Cahn–Hilliard modelAurore Naso & Lennon Ó Náraigh
We use the Navier–Stokes–Cahn–Hilliard model equations to simulate phase separation with flow. We study coarsening — the growth of extended domains wherein the binary mixture phase separates into its (...) |
 Article dans Phys. Rev. Fluids (2018) Turbulence and turbulent pattern formation in a minimal model for active fluidsMartin James, Wouter J. T. Bos, and Michael Wilczek
Active matter systems display a fascinating range of dynamical states, including stationary patterns and turbulent phases. While the former can be tackled with methods from the field of pattern (...) |
 Article dans J. Fluid Mech. (2018) Instability of pressure-driven gas–liquid two-layer channel flows in two and three dimensionsLennon Ó Náraigh & Peter D. M. Spelt
We study unstable waves in gas–liquid two-layer channel flows driven by a pressure gradient, under stable stratification, not assumed to be set in motion impulsively. The basis of the study is (...) |
2017
 Article dans Phys. Rev. Fluids (2017) Interaction between a large buoyant bubble and turbulenceAurore Loisy and Aurore Naso
The free rise of isolated, deformable, finite-size bubbles in otherwise homogeneous isotropic turbulence is investigated by direct numerical simulation. The Navier-Stokes equations are solved in (...) |
 Article dans J. Fluid Mech. (2017) Buoyancy-driven bubbly flows : ordered and free rise at small and intermediate volume fractionAurore Loisy, Aurore Naso and Peter D. M. Spelt
Various expressions have been proposed previously for the rise velocity of gas bubbles in homogeneous steady bubbly flows, generally a monotonically decreasing function of the bubble volume (...) |
 Article dans Phys. Rev. Fluids (2017) Directional change of fluid particles in two-dimensional turbulence and of football playersBenjamin Kadoch, Wouter J. T. Bos, and Kai Schneider
Multiscale directional statistics are investigated in two-dimensional incompressible turbulence. It is shown that the short-time behavior of the mean angle of directional change of fluid (...) |
 Article dans Phys. Rev. Lett. (2017) Statistical Model for the Orientation of Nonspherical Particles Settling in TurbulenceK. Gustavsson, J. Jucha, A. Naso, E. Lévêque, A. Pumir, and B. Mehlig
The orientation of small anisotropic particles settling in a turbulent fluid determines some essential properties of the suspension. We show that the orientation distribution of small heavy (...) |
2016
 Article dans Flow Turbul. Combust. (2016) Acceleration statistics of finite-size particles in turbulent channel flow in the absence of gravityWenchao Yu, Ivana Vinkovic & Marc Buffat
The interaction between finite-size particles and turbulent channel flow in the absence of gravity is studied here by direct numerical simulation. The turbulent flow is resolved by an efficient (...) |
 Article dans Europhys. Lett. (2016) Spread of consensus in self-organized groups of individuals : Hydrodynamics mattersAlessandro De Rosis, Emmanuel Lévêque, Francesco Ubertini & Sauro Succi
Nature routinely presents us with spectacular demonstrations of organization and orchestrated motion in living species. Efficient information transfer among the individuals is known to be (...) |
 Article dans J. Therm. Sci. Eng. Appl. (2016) Active Insulation Technique Applied to the Experimental Analysis of a Thermodynamic Control System for Cryogenic Propellant StorageSamuel Mer, Jean-Paul Thibault & Christophe Corre
A technological barrier for long-duration space missions using cryogenic propulsion is the control of the propellant tank self-pressurization (SP). Since the cryogenic propellant submitted to (...) |
 Article dans J. Turbul. (2016) Finite-size particles in turbulent channel flow : quadrant analysis and acceleration statisticsWenchao Yu, Ivana Vinkovic & Marc Buffat
The interaction between finite-size particles and turbulent channel flow in the absence of gravity is studied by direct numerical simulations (DNS). The study is motivated by DNS observations of (...) |
 Article dans Cryogenics (2016) Optimal design of a thermodynamic vent system for cryogenic propellant storageSamuel Mer, David Fernandez, Jean-Paul Thibault & Christophe Corre
Future operations in space exploration require to store cryogenic liquids for long duration. Residual heat loads, due to heat conduction in the launcher structure or solar radiation, induce (...) |
2015
 Article dans J. Turbul. (2015) Collision rate for suspensions at large Stokes numbers – comparing Navier–Stokes and synthetic turbulenceMichel Voßkuhle, Alain Pumir, Emmanuel Lévêque & Michael Wilkinson
The use of simplified models of turbulent flows provides an appealing possibility to study the collision rate of turbulent suspensions, especially in conditions relevant to astrophysics, which (...) |
 Article dans Phys. Rev. E (2015) Flow-parametric regulation of shear-driven phase separation in two and three dimensionsLennon Ó Náraigh, Selma Shun & Aurore Naso
The Cahn-Hilliard equation with an externally prescribed chaotic shear flow is studied in two and three dimensions. The main goal is to compare and contrast the phase separation in two and three (...) |
 Article dans Int. J. Multiph. Flow (2015) Numerical study of a flapping liquid sheet sheared by a high-speed streamNicolas Odier, Guillaume Balarac, Christophe Corre & Vincent Moureau
A numerical study of a liquid sheet sheared on both sides by a high-speed stream is performed in this work, at moderate density and velocity ratio between phases. Near the injection, an (...) |