# 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 :

Mahendra K. Verma, I. I. T. Kanpur, Inde

### Phenomenology of turbulent thermal convection

Jeudi 24 mai 2018, 13h, ECL, bât I11, salle de réunion RDC

In this talk I will provide an overview of the recent developments on turbulent convection, namely—
(1) Using pseudospectral simulations of turbulent thermal convection at very high resolution (...)

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ERCOFTAC/ Henri Bénard/ SIG 35/ SIG 39/ Workshop at École Centrale de Lyon

### A systems approach to turbulence and interactions, from single phase flow to two-phase flow

du Mercredi 30 Mai au Vendredi 1er juin 2018

The workshop will take place at Ecole Centrale de Lyon, Ecully, France. The whole event will combine a SIG 35/ERCOFTAC workshop (30-31/5), and a meeting of the Henri Bénard Pilot Center (1/6). (...)

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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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Article dans J. Fluid Mech. (2018)

### Scaling laws for mixing and dissipation in unforced rotating stratified turbulence

Annick Pouquet, Duane Rosenberg, Raffaele Marino and Corentin Herbert

We present a model for the scaling of mixing in weakly rotating stratified flows characterized by their Rossby, Froude and Reynolds numbers , $Ro$, $Fr$, $Re$. This model is based on (...)

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