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

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

## Wouter Bos

Groupe de Recherche : Turbulence & Instabilités
tél : 04.72.18.62.04
email

Research in the spotlight :

### Dissipation in unsteady turbulence (with R. Rubinstein)

Recent experiments and simulations have shown that unsteady turbulent flows display a universal behavior at short and intermediate times, different from classical scaling relations. The origin of these observations is explained and the exact form of the observed universal scaling is derived. The derived scaling for the normalized dissipation rate $C_\epsilon$ as a function of the Reynolds number $R_\lambda$ is,

$$C_\epsilon\sim R_\lambda^{-15/14},$$

and this perfectly fits the data of a large number of experiments, which were until now unexplained !!

Our prediction for the dependence of the dissipation rate on the Reynolds number perfectly fits (until now unexplained) experimental data.