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.