Forced two-dimensional turbulence in spectral and physical space - art. no. 061208

Two-dimensional (2D) turbulence in the energy range exhibits nonuniversal f eatures, manifested in the departure (at low k) from the k(-5/3) energy spe ctrum law, variable energy flux, and irregular, nonlocal transfers. To unra vel the underlying mechanism we conducted a detailed study of the 2D turbul ence in spectral and physical space. It revealed complex multiscale organiz ation of vorticity held and dynamic processes, ranging from large-scale mea ndering jets to strong localized vortices. The latter bear prime responsibi lity for the nonuniversal behavior of 2D turbulence, and we examined their statistical features and the growth mechanism. Our results are based on the numeric simulation of 2D turbulence on the 512 grid under different forcin g-dissipation conditions.