Effects of friction on 2D turbulence: An experimental study of the direct cascadeG. Boffetta1, A. Cenedese2, S. Espa2 and S. Musacchio3
1 Dipartimento di Fisica Generale and INFN, Università degli Studi di Torino Via Pietro Giuria 1, I-10125 Torino, Italy
2 Dipartimento di Idraulica, Trasporti e Strade, Università "La Sapienza" Via Eudossiana 18, I-00184 Roma, Italy
3 Dipartimento di Fisica, Università "La Sapienza" P.le A. Moro 2, I-00185 Roma, Italy
received 24 March 2005; accepted in final form 9 June 2005
published online 13 July 2005
We study the direct enstrophy cascade in a two-dimensional flow generated in an electromagnetically driven thin layer of fluid. Due to the presence of bottom friction, the energy spectrum deviates from the classical Kraichnan prediction k-3. We find that the correction to the spectral slope depends on the thickness on the layer, in agreement with a theoretical prediction based on the analogy with passive scalar statistics.
47.27.Gs - Isotropic turbulence; homogeneous turbulence.
47.52.+j - Chaos.
© EDP Sciences 2005