Abstract
Freely evolving two-dimensional turbulence is dominated by coherent vortices. The density of these vortices decays in time as ρ∼ 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 and their average radius as . The total energy is constant, the enstrophy decreases as , and the vorticity kurtosis increases as . These results are supported both by numerical simulations of the fluid equations and by solutions of a modified point-vortex model.
- Received 2 January 1991
DOI:https://doi.org/10.1103/PhysRevLett.66.2735
©1991 American Physical Society