# Séminaire de Mécanique d'Orsay

## Le Jeudi 12 novembre à 14h00 - Salle de conférences du FAST

### Non-equilibrium turbulence dissipation and self-preservation

## J. Christos Vassilicos

Dept. of Aeronautics, Imperial College London

Kolmogorov's (1941) theory of turbulence is an equilibrium theory which predicts scalings of the turbulent kinetic energy dissipation rate as u'^3/L where u'^2 is the turbulent kinetic energy and L is an integral length-scale. However, wind tunnel experiments of turbulence generated by various types of grids since 2007 have revealed the existence of different, non-equlibrium, scalings of the turbulence dissipation. Direct Numerical Simulations of periodic turbulence confirm these non-equilibrium dissipation scalings in a different turbulent flow. Furthermore, these non-equilibrium dissipation scalings are also present in axisymmetric turbulent wakes. Combined with minimal self-preservation, they imply new mean flow scalings for such wakes which are found with wind tunnel experiments.