Revisiting freely decaying two-dimensional turbulence at millennial resolution

We study the evolution of vortex statistics in freely decaying two-dimensio nal turbulence at very large Reynolds number. The results obtained here con firm that the peak vorticity inside vortex cores is conserved and that the number of vortices as a function of time, N(t), decreases as a power law. I n addition, the numerical findings are consistent with the predictions of t he scaling theories proposed by Carnevale [Phys. Rev. Lett. 66, 2735 (1991) ] and Weiss and McWilliams [Phys. Fluids A 5, 608 (1993)]. We also obtain n ew evidence for a self-similar distribution of vortex radii and circulation s, that suggests the possibility of a generic statistical behavior of the d ecaying phase of two-dimensional turbulence at high Reynolds number. (C) 20 00 American Institute of Physics. [S1070-6631(00)50711-9].