# Laboratoire de Mécanique des Fluides et d’Acoustique - UMR 5509

LMFA - UMR 5509
Laboratoire de Mécanique des Fluides et d’Acoustique
Lyon
France

## Turbulence & Instabilités

Responsable : Florence Raynal

Les activités de l’équipe, à caractère plutôt fondamentales, concernent l’analyse des instabilités hydrodynamiques, la transition laminaire/turbulence, les écoulements turbulents, et les écoulements à petite échelle.

Les actualités de T&I :

Habilitation à diriger des recherches ECL

### Florence RAYNAL

Mardi 26 juin 2018 – 10h00 – ECL – Amphi 3

Systèmes dynamiques, mélange et applications : quelques facettes de l’advection chaotique.
Jury :
Patrice MEUNIER, IRPHE, Aix-Marseille Université, Rapporteur ;
Alain PUMIR, Laboratoire de (...)

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Article dans J. Fluid Mech. (2018)

### Instability of pressure-driven gas–liquid two-layer channel flows in two and three dimensions

Lennon 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 (...)

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Article dans J. Biomechanics (2018)

### Comparison between a generalized Newtonian model and a network-type multiscale model for hemodynamic behavior in the aortic arch : Validation with 4D MRI data for a case study

Marine Menut, Loïc Boussel, Xavier Escriva, Benyebka Bou-Saïd, Hélène Walter-Le Berre, Yann Marchesse, Antoine Millon, Nellie Della Schiava, Patrick Lermusiaux, John Tichy

Blood is a complex fluid in which the presence of the various constituents leads to significant changes in its rheological properties. Thus, an appropriate non-Newtonian model is advisable ; and (...)

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Article dans J. Fluid Mech. (2018)

### A note on Stokes’ problem in dense granular media using the $\mu(I)$-rheology

J. 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 (...)

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Article dans J. Fluid Mech. (2018)

### Advection and diffusion in a chemically induced compressible flow

Florence Raynal, Mickaël Bourgoin, Cécile Cottin-Bizonne, Christophe Ybert & Romain Volk

We study analytically the joint dispersion of Gaussian patches of salt and colloids in linear flows, and how salt gradients accelerate or delay colloid spreading by diffusiophoretic effects. (...)

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Article dans Phys. Lett. A (2018)

### Theories and applications of second-order correlation of longitudinal velocity increments at three points in isotropic turbulence

J.Z. Wu, L. Fang, L. Shao & L.P. Lu

In order to introduce new physics to traditional two-point correlations, we define the second-order correlation of longitudinal velocity increments at three points and obtain the analytical (...)

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Article dans Phys. Plasmas (2018)

### On the role and value of $\beta$ in incompressible MHD simulations

Robert Chahine & Wouter J. T. Bos

The parameter $\beta$, defined as the ratio of the pressure to the square of the magnetic field, is widely used to characterize astrophysical and fusion plasmas. However, in the dynamics of a (...)

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Article dans J. Stat. Mech. (2018)

### Computing return times or return periods with rare event algorithms

Thibault Lestang, Francesco Ragone, Charles-Edouard Bréhier, Corentin Herbert & Freddy Bouchet

The average time between two occurrences of the same event, referred to as its return time (or return period), is a useful statistical concept for practical applications. For instance insurances (...)

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Article dans J. Fluid Mech. (2018)

### Collision rate of ice crystals with water droplets in turbulent flows

Aurore 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 (...)

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Article dans J. Turbul. (2018)

### Advanced lattice Boltzmann scheme for high-Reynolds-number magneto-hydrodynamic flows

Alessandro De Rosis, Emmanuel Lévêque & Robert Chahine

Is the lattice Boltzmann method suitable to investigate numerically high-Reynolds-number magneto-hydrodynamic (MHD) flows ? It is shown that a standard approach based on the Bhatnagar–Gross–Krook (...)

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Article dans J. Stat. Mech. (2018)

### Computing return times or return periods with rare event algorithms

Thibault Lestang, Francesco Ragone, Charles-Edouard Bréhier, Corentin Herbert & Freddy Bouchet

The average time between two occurrences of the same event, referred to as its return time (or return period), is a useful statistical concept for practical applications. For instance insurances (...)

Lire la suite

Article dans J. Fluid Mech. (2018)

### Space–time dynamics of optimal wavepackets for streaks in a channel entrance flow

Frédéric Alizard, Anne Cadiou, Lionel Le Penven, Bastien Di Pierro & Marc Buffat

The laminar–turbulent transition of a plane channel entrance flow is revisited using global linear optimization analyses and direct numerical simulations. The investigated case corresponds to (...)

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