Volume 80, Number 5, December 2007
Article Number 54001
Number of page(s) 6
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
Published online 25 October 2007
EPL, 80 (2007) 54001
DOI: 10.1209/0295-5075/80/54001

Sub-Kolmogorov-scale fluctuations in fluid turbulence

J. Schumacher

Department of Mechanical Engineering, Technische Universität Ilmenau - D-98684 Ilmenau, Germany

received 4 July 2007; accepted in final form 1 October 2007; published December 2007
published online 25 October 2007

We relate the intermittent fluctuations of velocity gradients in turbulence to a whole range of local dissipation scales generalizing the picture of a single mean dissipation length. The statistical distribution of these local dissipation scales as a function of Reynolds number is determined in numerical simulations of forced homogeneous isotropic turbulence with a spectral resolution never applied before which exceeds the standard one by at least a factor of eight. The core of the scale distribution agrees well with a theoretical prediction. Increasing Reynolds number causes the generation of ever finer local dissipation scales. This is in line with a less steep decay of the large wave number energy spectra in the dissipation range. The energy spectrum for the highest accessible Taylor microscale Reynolds number $R_{\lambda}$ = 107 does not show a bottleneck.

47.27.Gs - Isotropic turbulence; homogeneous turbulence.
47.27.E- - Turbulence simulation and modeling.
47.27.eb - Statistical theories and models.

© Europhysics Letters Association 2007