# 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:

École doctorale thématique de l’AUM

### Outils transversaux pour la mécanique 2020 REPORTÉ EN 2021

Villeurbanne, Amphithéâtre du Bâtiment FREYSSINET, du lundi 5 au mercredi 7 juillet 2021

L’école doctorale thématique se déroulera du 5 au 7 Juillet 2021 en partenariat avec les écoles doctorales MEGA et MATERIAUX de Lyon. Elle a pour objectif de proposer une formation scientifique à (...)

Article in Comput. Math. Appl.. (2021)

### Recursive finite-difference Lattice Boltzmann schemes

Lucien Vienne & Emmanuel Lévêque

The motivation of this study is twofold. First, a recursive mathematical formulation of the discrete-velocity Boltzmann equation (DVBE) under the Bhatnagar-Gross-Krook (BGK) approximation is (...)

Article in Phys. Rev. E (2021)

### Spontaneous generation and reversal of helicity in anisotropic turbulence

Wesley Agoua, Benjamin Favier, Alexandre Delache, Antoine Briard & Wouter Bos

Helicity plays an important role in spectacular geophysical phenomena such as hurricanes or the generation of the terrestrial magnetic field. The present investigation shows how helicity can be (...)

Article in MNRAS (2021)

### Comparing turbulence in a Kelvin–Helmholtz instability region across the terrestrial magnetopause

Paulina Quijia, Federico Fraternale, Julia E Stawarz, Christian L Vásconez, Silvia Perri, Raffaele Marino, Emiliya Yordanova & Luca Sorriso-Valvo

The properties of turbulence observed within the plasma originating from the magnetosheath and the magnetospheric boundary layer, which have been entrained within vortices driven by the (...)

Article in Phys. Rev. Fluids (2021)

### Lattice Boltzmann study of miscible viscous fingering for binary and ternary mixtures

Lucien Vienne, Simon Marié

A lattice Boltzmann simulation of a viscous fingering instability with miscible components is performed. The core ingredients of the instability are related to the molecular diffusion and the (...)

Article in J. Fluid Mech. (2021)

### Model for thermal convection with uniform volumetric energy sources

Mathieu Creyssels

A theoretical model is derived to predict the heat fluxes at the upper and lower horizontal surfaces of an internally heated (IH) convection cell by extending the well-known Grossmann & Lohse (...)

Article in J. Turbulence (2021)

### Transition from axisymmetric to three-dimensional turbulence

Zecong Qin, Aurore Naso & Wouter Bos

In purely axisymmetric turbulence sustained by a linear forcing mechanism, a stable, entirely poloidal flow is observed when the toroidal component of the forcing is below a threshold. We (...)

Article in Q. J. Mech. Appl. Math. (2020)

### Calculation of a key function in the asymptotic description of moving contact lines

Julian Scott

An important element of the asymptotic description of flows having a moving liquid/gas interface which intersects a solid boundary is a function denoted $Q_i(\alpha)$ by Hocking and Rivers (The (...)

Article in J. Fluid Mech. (2021)

### Three-dimensional turbulence without vortex stretching

Wouter Bos

We consider three-dimensional turbulence from which vortex stretching is removed. The resulting system conserves enstrophy, but does not conserve kinetic energy. Using spectral closure, it is (...)

Article in Phys. Rev. Fluids (2021)

### Scalar mixing in homogeneous isotropic turbulence: A numerical study

Michel Orsi, Lionel Soulhac, Fabio Feraco, Massimo Marro, Duane Rosenberg, Raffaele Marino, Maurizio Boffadossi & Pietro Salizzoni

The understanding of the mechanics of turbulent dispersion is of primary importance in estimating the effects of mixing processes involved in a variety of events playing a significant role in our (...)

Article in Int. J. Heat Mass Transf. (2021)

### Acoustic streaming enhanced mass transfer at a wall

Nouhayla El Ghani, Sophie Miralles, Valéry Botton, Daniel Henry, Hamda Ben Hadid, Benoît Ter-Ovanessian & Sabrina Marcelin

The influence of an impinging acoustic streaming jet on wall mass transfer is studied both experimentally and numerically. The idea is to show that acoustically-driven jets generated by (...)

Article in Comput. Mech. (2021)

### Modeling the role of clusters and diffusion in the evolution of COVID-19 infections during lock-down

Wouter Bos, Jean-Pierre Bertoglio & Louis Gostiaux

The dynamics of the spread of epidemics, such as the recent outbreak of the SARS-CoV-2 virus, is highly nonlinear and therefore difficult to predict. As time evolves in the present pandemic, it (...)