Laboratoire de Mécanique des Fluides et d'Acoustique - UMR 5509

Informations pratiques

Gostiaux Louis — 2100-10-17T10:08:00Z

Les séminaires du LMFA ont lieu le vendredi à 11h, et s'adressent à l'ensemble du laboratoire.
contact : louis.gostiaux@ec-lyon.fr, wouter.bos@ec-lyon.fr, benjamin.miquel@ec-lyon.fr
Pour accéder au laboratoire voir ici

Documents utiles :

Séminaires T&I

2027-03-03T16:25:00Z

Les séminaires de l'équipe se tiennent le jeudi de 12h00 à 12h45. Une présentation de 30 min, laissant place aux questions et échanges. Un séminaire sur trois est donné sur le campus de la DOUA.

Pour s'abonner au calendrier des séminaires, vous pouvez utiliser ce lien Ical

Vous pouvez retrouver les anciens séminaires ici

Séminaire informel

Romain Vallon

Vendredi 18 juillet 2025 à 13h, ECL, bât. I11, salle de conférence du bas

Accélération GPU pour le calcul des fonctions de structures
Les volumes de données générés à l'aide de DNS sont conséquents. Le traitement de ces données peut être long (quelques heures), voire très long (...)

Séminaires passés 2024 :

Séminaire informel T&I

Mathieu Creyssels

Vendredi 3 Mai 2024 à 14h, ECL, bât. I11, salle de conférence du bas

Mélange turbulent et entraînement dans les jets, panaches et courants de gravité
Le mélange turbulent est le processus physique qui contrôle la dispersion des espèces chimiques dans les écoulements (...)

Séminaire informel T&I

Joran Rolland

Lundi 6 mai, 14h, salle B11, bât. H10, ECL

Using learnt stochastic model to study the regime change of a bistable wake
When two parallel bars of thickness H, in a flow at Reynolds number R $= HU/\nu\simeq 10000$, are brought close enough (...)

Séminaire informel T&I

Anne Sergent

Mardi 7 mai, 14h, salle B11, bât. H10, ECL

Panaches et circulation à grande échelle en convection turbulente asymétrique : modélisation HPC et apprentissage automatique
Les écoulements de convection naturelle sont présents aussi bien en (...)

Séminaire informel T&I

Jérôme Boudet

Lundi 13 mai, 10h, salle B11, bât. H10, ECL

Écoulements tourbillonnaires à haut Re : méthodes et analyses en simulation des grandes échelles.
L'aérodynamique repose des écoulements tourbillonnaires, généralement à haut nombre de Reynolds, et donc (...)

Séminaire informel T&I

Annick Pouquet

Mercredi 29 Mai à 11h, Salle B11, bât. H10, ECL

Some characteristics of intermittency for energy dissipation : ideas and results
Our understanding of turbulence has progressed significantly through combining experiments, observations, (...)

Visualisations scientifiques

Vincent Hugo — 2026-09-09T16:30:25Z

Vincent Hugo — 2026-09-09T16:25:58Z

https://www.linkedin.com/in/hugo-vincent-34a395376/

- Vincent Hugo

PhD proposal : Energy Transfer in Turbulent Space Plasmas

Scolan Hélène — 2026-09-01T09:32:45Z

Inverse modelling of atmospheric dispersion and soil deposition of PFAS for source identification

Supervisor : Dr. Raffaele Marino (LMFA, ECL)

Link for application : lien vers emploi.cnrs

Application Deadline : 18 September 2026 23:59

Scientific context :

Approximately 99% of the visible Universe is made of plasma, an ionized gas of charged particles corresponding to the “fourth state” of matter. Plasmas are ubiquitous in nature, from the solar corona and solar wind to planetary magnetospheres and stellar systems. They are also at the core of several strategic technologies, such as nuclear fusion and cutting-edge medical devices. Despite the diversity of the environments in which they exist or are created, plasmas share a fundamental property : their dynamics are strongly nonlinear and characterised by interactions over a broad range of spatial and temporal scales.

In particular, space plasmas are highly turbulent systems in which energy is continuously injected, transferred through nonlinear interactions between the different scales involved in their dynamics, and eventually dissipated. At the smallest scales, kinetic effects become increasingly important, and the energy ultimately contributes to plasma heating and is transferred to ions and electrons through various mechanisms, including magnetic reconnection and wave-particle interactions. Energy exchanges among kinetic, magnetic and thermal components also play an important role in the dynamics of turbulent plasmas.

Characterising energy transfer in space plasmas, from the sources of energy, through the direction of the energy cascade, to dissipation, remains a fundamental open problem in plasma physics. In particular, the connection between turbulent cascades at magnetohydrodynamic (MHD) scales and the phenomena responsible for energy transfer and dissipation at kinetic scales is only partially understood. Given the complexity of this highly nonlinear framework, a comprehensive characterisation of how energy is redistributed across the vast dynamical range of scales, from the scales characteristic of solar and heliospheric phenomena down to ion and electron scales, as well as the investigation of direct and inverse energy transfers in space plasmas, requires a thorough assessment of energy fluxes, quadratic quantities based on velocity and magnetic fields, and the analysis of plasma-wave propagation. This can be enabled by combining state-of-the-art spacecraft observations, high-resolution numerical simulations and theoretical modelling.
Objectives :

The main objective of this PhD is to quantitatively characterise energy transfer in space plasmas using datasets from single- and multi-spacecraft missions, high-performance computing and advanced theoretical approaches, in order to investigate the evolution of turbulence in the solar wind and planetary environments, such as the Earth's magnetosphere, and its interplay with the propagation of plasma waves. The project will focus on the investigation of the spectral and statistical properties of turbulence, intermittency, and the signatures of coherent structures, magnetic reconnection and wave propagation. Using high-resolution numerical simulations, the relevant physical mechanisms identified through the analysis of spacecraft observations will be studied over a range of parameters of direct relevance to solar-wind and magnetospheric plasmas. In particular, the energy flow from the MHD range to regimes in which kinetic effects become important will be investigated, as well as the main mechanisms responsible for energy dissipation and energy conversion at ion and electron scales.

Methodology :

The project will combine spacecraft-data analysis, high-resolution numerical simulations and theoretical modelling. Spacecraft datasets will be used to characterise fluctuations of the magnetic, velocity and other relevant fields, as well as the evolution of the probability distribution functions of different plasma species. Observations from European Space Agency (ESA) missions, in particular Solar Orbiter, as well as from JAXA and NASA missions, will be analysed within the project. Preparatory research in support of future missions, such as Plasma Observatory and HelioSwarm, will also be carried out.

Depending on the physical regime considered, several numerical approaches may be employed, including pseudo-spectral, lattice-Boltzmann and kinetic Vlasov simulations. These will make it possible to explore a range of parameters directly relevant to heliospheric and magnetospheric plasmas and to characterise the mechanisms investigated through spacecraft observations.

The tools developed within the project will be used to assess inter-scale energy transfers, energy exchanges among kinetic, magnetic and thermal components, and statistical properties of plasma fields in space. Machine-learning techniques will be implemented for the analysis of large observational and numerical datasets, in synergy with classical statistical analyses and novel mathematical methodologies.
Impact :

This work will provide new insight into the mechanisms governing energy transfer and dissipation in turbulent space plasmas. In the longer term, the results will contribute to improving models for the evolution of solar and heliospheric plasmas and therefore help improve the quality of space-weather predictions and support the preparation of future space missions, in particular the ESA Plasma Observatory mission, through the development of tools for analysing large observational datasets.

Achieving a better understanding of how energy is transferred and how different types of instabilities develop in turbulent plasmas is also of broader relevance to plasma physics and technological applications, including fusion plasmas. Characterising turbulent transport and nonlinear interactions between structures at different scales are indeed common challenges in astrophysical and laboratory plasmas. The results obtained in this project may therefore contribute to strengthening links between the communities working on astrophysical, fusion and fundamental plasmas.

More details and for application, see :
lien vers site emploi cnrs

Gas injection into confined porous layers : compressibility and curvature

Miquel Benjamin — 2026-08-27T14:51:59Z

Motivated by the use of underground hydrogen storage as a renewable energy technology, I will present a theoretical model of gas injection into a liquid-filled porous channel. In an underground aquifer, hydrogen's low viscosity compared with the resident brine causes a bubble of hydrogen trapped beneath caprock to spread rapidly through release of a thin gas layer above the brine, complicating recovery. I will show how gas compressibility and the curvature of a dome-shaped aquifer can be incorporated in reduced-order models of injection dynamics. In long aquifers, the large viscous pressure drop between source and outlet induces significant pressure variations, potentially leading to substantial density changes in the injected gas. Compression of the main gas bubble can generate dynamic pressure changes that are coupled to those in the thin gas layer that spreads over the liquid, reducing spreading rates and gas pressures. In curved channels, buoyancy influences the dynamics through distinct mechanisms : in an axisymmetric channel with a Gaussian profile, buoyancy acts continually on the flow in a self-similar manner, whereas in a parabolic channel, buoyancy operates across five temporal regimes, which are described through a sequence of asymptotic approximations.

References : Castellucci et al. 2026 J. Fluid Mech. 1029, A28 ; arXiv:2604.20007.

PhD proposal (2026-2030) : Droplet Redistribution by Rolling Wheels

Scolan Hélène — 2026-07-10T08:06:45Z

Fully funded 4-year experimental PhD in fluid mechanics and soft matter physics
LMFA – Université Claude Bernard Lyon 1 (Lyon, France)
In collaboration with the University of Cambridge (UK) and the Defence Science and Technology Laboratory (Dstl, UK)

Research subject : Droplet Redistribution by Rolling Wheels

Main supervisor : Prof. Julien LANDEL (LMFA, UCBL)

Locations : Laboratory of Fluid Mechanics and Acoustics (LMFA), Université Claude Bernard Lyon 1, Doua campus, Villeurbanne, France,

Collaboration : University of Cambridge (UK) and the Defence Science and Technology Laboratory (Dstl, UK)

Key information
• Start date : October 2026 – January 2027
• Duration : 4 years
• Funding : industrial sponsor Defence Science and Technology Laboratory (Dstl, UK)
• Research area : Experimental fluid mechanics, multiphase flows, soft matter physics
• Supervision : Prof. Julien LANDEL (LMFA, UCBL), Prof. Jean-Philippe Matas (LMFA, UCBL), Prof. Stuart Dalziel (DAMTP, University of Cambridge)

Project description :
This PhD project aims to uncover the fundamental mechanisms governing the transfer and redistribution of liquid droplets by rolling wheels on contaminated surfaces.
The project will investigate how droplets deform, spread, break up, and are redistributed through a combination of :
• capillary effects,
• inertial forces,
• centrifugal effects,
• interfacial instabilities.
The research will combine high-speed imaging experiments, experimental fluid mechanics, scaling analysis, and modelling to develop a physical understanding of droplet transfer processes.
The project will focus on several key phenomena :
• formation of thin liquid films under wheel contact,
• dynamics and breakup of capillary bridges,
• droplet ejection mechanisms,
• transport and redistribution of liquid by rotating surfaces.
A major outcome will be the development of new experimental approaches and physical models for multiphase contamination and decontamination processes.

More details for application, see :

ALCOTRA 0Plastique - Améliorer la protection et la conservation de la nature et de la biodiversité en atténuant la pollution des plastiques et des micro-plastiques dans les milieux alpins

Del Ponte Annika Vittoria — 2026-07-09T13:38:21Z

Le projet ALCOTRA 0Plastique est un projet européen, qui vise à protéger la biodiversité des milieux alpins italo-français en réduisant la pollution par les plastiques et les micro-plastiques. Le projet durera trois ans (05/2026 – 05/2029), lors desquels différentes activités seront développées : la collecte des déchets le long des sentiers et dans les lacs alpins, la mise en place d'un système de suivi fondé sur des bioindicateurs (notamment, animaux sauvages) et des capteurs de qualité de l'air, accroître la sensibilisation des jeunes, des acteurs économiques et des touristes aux impacts de la pollution par les plastiques dans les milieux alpins.
Le projet s'articule en cinq GT. Le GT1 porte sur la gouvernance et gestion administrative, en garantissant une coordination efficace des activités. Le GT2 est dédié à la communication, pour informer et engager les différents stakeholders. Le GT3 prévoit des activités éducatives visant à favoriser la protection de la biodiversité, tandis que le GT4 développe et expérimente des actions innovantes pour sa conservation. Finalement, le GT5 prévoit interventions spécifiques pour lutter contre la pollution par les plastiques dans les habitats alpins.
Parmi les résultats attendus, on remarque : la diffusion de pratiques durables telles que la réduction, la réutilisation et le recyclage des plastiques ; la collecte systématique de données scientifiques sur les niveaux de plastiques et de micro-plastiques dans les ongulés et les écosystèmes aquatiques alpins ; renforcement de la protection de la faune ; suivi et réduction des déchets plastiques dans les lacs et les habitats montagneux ; et l'amélioration de l'état de conservation des écosystèmes et de la biodiversité.

Partenaire :
Fondazione European Research Institute ETS
Istituto d'Istruzione Superiore Erasmo da Rotterdam
Università degli Studi di Torino
Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta
CDE Petra Patrimonia
Association Mountain Riders
Ecole Centrale de Lyon

Site web :
https://www.interreg-alcotra.eu/it/alcotra-0plastique-migliorare-la-protezione-e-la-conservazione-della-natura-e-della-biodiversita

Smiron Varghese

Bos Wouter — 2026-07-07T14:53:15Z

Linear Analysis of Rotating Double-Diffusive Convection

Jury :

Sébastien AUMAÎTRE, Directeur de recherche, CEA (SPEC) Rapporteur
Le FANG, Professeur, (Ecole Centrale Pekin) Rapporteur
Florence RAYNAL, Directrice de recherche, CNRS (LMFA) Examinatrice
Jérémie VIDAL, Chargé de recherche, CNRS (LGL-TPE) Examinateur
Wouter BOS, Directeur de recherche, CNRS (LMFA) Directeur de thèse
Benjamin MIQUEL, Chargé de recherche, CNRS (LMFA) Co-directeur de thèse

Résumé :

This thesis examines the influence of rotation on the salt-fingering branch of double-diffusive instability in stably stratified fluid layers of geophysical and astrophysical rel-evance. In many planetary cores and stellar interiors, density depends simultaneously on temperature and composition. The marked disparity between their diffusivities can destabilize a layer that would otherwise remain stable to ordinary overturning convection. The manner in which rapid rotation modifies this instability remains incompletely understood. The present work addresses this question in a plane-layer geometry.

A central part of the work is devoted to a detailed linear stability analysis of rotating double-diffusive convection. The instability is studied through normal-mode analysis in a wall-bounded layer with impenetrable horizontal boundaries. In the rapidly rotating limit, the study shows how rotation alters both the threshold and the spatial structure of the instability, leading to a progressive shift toward smaller horizontal scales. Reduced descriptions are then derived in the limits of large Lewis number and large Schmidt number, which are especially pertinent to astrophysical and liquid-metal contexts. Numerical linear stability shows that these results are roughly insensitive to the exact type of boundary conditions at the wall. Preliminary results using direct numerical simulations are used to illustrate the dynamics of the nonlinear saturated regime.

The manuscript also explores the question of helicity amplification in the rotating fingering system. A linear analysis is performed in a 2D3C limit to assess possible mechanisms of helicity growth in the absence of solid walls.

Journée des doctorant.e.s du LMFA 2026

Scolan Hélène — 2026-07-07T12:50:12Z

Jeudi 9 juillet sur le campus de Centrale Lyon a lieu la journée des doctorant.e.s du LMFA.

Cette journée est l'occasion :

de découvrir ou redécouvrir quelques activités de recherche faites par les doctorants au sein du laboratoire
d'échanger sur les difficultés et les astuces que l'on peut rencontrer pendant une thèse
de partager un moment convivial

Venez découvrir le travail des doctorants en amphi 3 !

Programme complet :

Programme JDD 2026

Laboratoire de Mécanique des Fluides et d'Acoustique - UMR 5509

Informations pratiques

Séminaires T&I

Romain Vallon

Mathieu Creyssels

Joran Rolland

Anne Sergent

Jérôme Boudet

Annick Pouquet

Visualisations scientifiques

LinkedIn

PhD proposal : Energy Transfer in Turbulent Space Plasmas

Gas injection into confined porous layers : compressibility and curvature

PhD proposal (2026-2030) : Droplet Redistribution by Rolling Wheels

ALCOTRA 0Plastique - Améliorer la protection et la conservation de la nature et de la biodiversité en atténuant la pollution des plastiques et des micro-plastiques dans les milieux alpins

Smiron Varghese

Linear Analysis of Rotating Double-Diffusive Convection

Journée des doctorant.e.s du LMFA 2026