# Fluid Mechanics and Acoustics Laboratory - UMR 5509

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

## Turbulence & Instabilities

The team activities, rather fundamental, deal with hydrodynamic instabilities, transition to turbulence, turbulent flows and flows at small scale.

T&I news:

Communication scientifique

### Des nageurs bien turbulents

Résultats mis en avant par l’American Physical Society

Pourrait-il y avoir un lien entre le comportement collectif d’entités capables de se déplacer de façon autonome (bactéries, animaux, foules, etc.) et la turbulence hydrodynamique ? Des chercheurs de (...)

### Posters doctorants 2A

Nos étudiants doctorants en 2ème année ont réalisé des posters didactiques pendant le confinement. Les consignes et le modèle sont donnés ici.
À défaut de pouvoir les accrocher sur les murs du labo pour (...)

Article in Phys. Rev. Fluids (2020)

### Transition from non-swirling to swirling axisymmetric turbulence

Zecong Qin, Hugues Faller, Bérengère Dubrulle, Aurore Naso & Wouter Bos

Strictly axisymmetric turbulence, i.e., turbulence governed by the Navier-Stokes equations modified such that the flow is invariant in the azimuthal direction, is a system intermediate between (...)

Article in Phys. Rev. Fluids (2020)

### Single-particle Lagrangian statistics from direct numerical simulations of rotating-stratified turbulence

Dhawal Buaria, Alain Pumir, Fabio Feraco, Raffaele Marino, Annick Pouquet, Duane Rosenberg & Leonardo Primavera

Geophysical fluid flows are predominantly turbulent and often strongly affected by the Earth’s rotation, as well as by stable density stratification. Using direct numerical simulations of forced (...)

Article in J. Fluid. Mech. (2020)

### Numerical study of extreme mechanical force exerted by a turbulent flow on a bluff body by direct and rare-event sampling techniques

Thibault Lestang, Freddy Bouchet & Emmanuel Lévêque

This study investigates, by means of numerical simulations, extreme mechanical force exerted by a turbulent flow impinging on a bluff body, and examines the relevance of two distinct rare-event (...)

Article in Atmosphere (2020)

### Partitioning Waves and Eddies in Stably Stratified Turbulence

Henri Lam, Alexandre Delache & Fabien Godeferd

We consider the separation of motion related to internal gravity waves and eddy dynamics in stably stratified flows obtained by direct numerical simulations. The waves’ dispersion relation links (...)

Article in J. Fluid. Mech. (2020)

### Analysis of turbulence characteristics in a temporal dense gas compressible mixing layer using direct numerical simulation

Aurélien Vadrot, Alexis Giauque & Christophe Corre

This study investigates the effects of a Bethe–Zel’dovich–Thompson (BZT) dense gas (FC-70) on the development of a turbulent compressible mixing layer at a convective Mach number $M_c=1.1$. (...)

Article in Journal of Turbulence (2020)

### Staircase scaling of short-time energy transfer in turbulence

Le Fang, T. Wu & Wouter Bos

It is illustrated that a sharply truncated initial kinetic energy spectrum evolves to a staircase-shaped spectrum at short times. This effect is directly associated with the triadic nature of the (...)

Article in Phys. Rev. E (2020)

### Efficiency of laminar and turbulent mixing in wall-bounded flows

Benjamin Kadoch, Wouter Bos & Kai Schneider

A turbulent flow mixes in general more rapidly a passive scalar than a laminar flow does. From an energetic point of view, for statistically homogeneous or periodic flows, the laminar regime is (...)

Article in Phys. Rev. Fluids (2020)

### Scaling laws in axisymmetric magnetohydrodynamic duct flows

Alexandre Poyé, Olivier Agullo, Nicolas Plihon, Wouter Bos, Victor Desangles & Guillaume Bousselin

We report on a numerical study of axisymmetric flow of liquid metal in a circular duct with a rectangular cross section. The flow is forced through the combination of an axial magnetic field and (...)