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

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

## Andrea Maffioli

Équipe de Recherche : Turbulence & Instabilités

Post-doc at LMFA with Fabien Godeferd and Alexandre Delache

I work on stably stratified turbulence using analytical methods and Direct Numerical Simulations (DNS). Most of my research consists in fundamental studies of ocean processes, such as mixing of the density field in the ocean pycnocline.

For my PhD at the University of Cambridge I carried out experiments in grid-stirred salt-stratified water and DNS to investigate localized regions of stratified turbulence, which decay in time and emit internal gravity waves in the ambient fluid. Our conclusions were that the internal waves are radiated ahead of stacks of horizontally growing intrusions and that they are quasi-linear, obeying the group speed relation. They are similar to fronts found in the atmosphere and could therefore be of more general relevance.

Density perturbation $\rho^\prime$ in a vertical slice through a 3D DNS of Kolmogorov flow with a linear stratification at initial gradient Richardson number $Ri_g = 0.2$. Onset of shear instability of laminar flow, showing both primary and secondary instabilities.

Cover image of JFM Vol. 786 (January 2016)