Issue
EPL
Volume 78, Number 3, May 2007
Article Number 34002
Number of page(s) 6
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
DOI http://dx.doi.org/10.1209/0295-5075/78/34002
Published online 27 April 2007
EPL, 78 (2007) 34002
DOI: 10.1209/0295-5075/78/34002

The structures responsible for the inverse energy and the forward enstrophy cascades in two-dimensional turbulence

C.-H. Bruneau1, P. Fischer1 and H. Kellay2

1  MAB, Université Bordeaux 1, CNRS UMR 5466, INRIA projet MC2 - 351 cours de la Libération, 33405 Talence, France
2  CPMOH, Université Bordeaux 1, CNRS UMR 5798 - 351 cours de la Libération, 33405 Talence, France


received 25 January 2007; accepted in final form 27 March 2007; published May 2007
published online 27 April 2007

Abstract
Two-dimensional turbulence admits two different ranges: an inverse energy cascade at large scales and a cascade of enstrophy to the small scales. Here we show that two flow structures govern the transfers of either enstrophy or energy. Vortical structures are responsible for the transfers of energy upscale while filamentary structures are responsible for the forward transfer of the enstrophy.

PACS
47.27.Ak - Fundamentals.
47.27.Gs - Isotropic turbulence; homogeneous turbulence.

© Europhysics Letters Association 2007