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.

The laboratory modelling of a rotating turbulent flow subjected to a β-effect by means of laboratory experiments is considered. In particular the focus has been put on the emergence and the evolution of zonal jet-like structures due to the anisotropization of the upscale energy transfer that can be observed in geophysical flows. The experimental setup consists of a rotating tank in which a turbulent flow is reproduced by electromagnetically forcing a shallow layer of saline solution; this model then reproduces the dynamics in the polar regions simulating the so-called γ-plane by the parabolic surface of the rotating fluid. Several experiments have been performed by changing the main external parameters in order to investigate if the setup is suitable for reproducing the basic dynamics associated with a banded configuration analogous to large scale atmospheric and oceanic circulations. Velocity measurements performed by image analysis have allowed characterization of the flow in terms of mean azimuthal velocity, degree of anisotropy, distribution of energy, and characteristic scales. As expected, zonal jets have been found to dominate the dynamics when the β-effect is stronger.