Evolution of vortex statistics in two-dimensional turbulence

This is the authors' abstract. We don't add key points for this paper.

Freely evolving two-dimensional turbulence is dominated by coherent vortices. The density of these vortices decays in time as {ρ}{~}t^-ξ with {ξ}{}0.75. A new scaling theory is proposed which expresses all statistical properties in terms of {ξ}. Thus the average circulation of the vortices increases as t^ξ/2 and their average radius as t^ξ/4. The total energy is constant, the enstrophy decreases as t^-ξ/2, and the vorticity kurtosis increases as t^ξ/2. These results are supported both by numerical simulations of the fluid equations and by solutions of a modified point-vortex model.