Intermittency in the Enstrophy Cascade of Two-dimensional Fully-developed Turbulence: Universal Features

Intermittency (externally induced) in the two-dimensional (2D) enstrophy cascade is shown to be able to maintain a finite enstrophy along with a vorticity conservation anomaly. Intermittency mechanisms of three-dimensional (3D) energy cascade and 2D enstrophy cascade in fully-developed turbulence (FDT) seem to have some universal features. The parabolic-profile approximation (PPA) for the singularity spectrum f(α) in multi-fractal model is used and extended to the appropriate microscale regimes to exhibit these features. The PPA is also shown to afford, unlike the generic multi-fractal model, an analytical calculation of probability distribution functions (PDF) of flowvariable gradients in these FDT cases and to describe intermittency corrections that complement those provided by the homogeneous fractal model. Permanent Address: University of Central Florida, Orlando, Florida