Correlations of vorticity inside a coherent vortex

Abstract

We examine fluctuations of vorticity inside the coherent vortex, appearing as a consequence of the inverse energy cascade in two-dimensional turbulence. Temporal and spacial correlations can be characterized by the pair correlation function. The interaction between the fluctuations leads to non-zero value of the third moment of vorticity. We examine the pair correlation function and the third moment for the model where the pumping is short correlated in time. We find explicit expressions for the Gaussian spacial correlation function of the pumping force. They confirm the general predictions obtained earlier.