A mean field prediction of the asymptotic state of decaying 2D turbulence

At sufficiently high Reynolds numbers, the formation of coherent structures in freely decaying two-dimensional incompressible flows eventually results in a quasi-stationary state. This state is stable and stationary, apart from slow dissipation by viscosity. This paper compares the quasi-stationary state obtained from a numerical integration of the two-dimensional Navier-Stokes equation, with predictions of a mean field theory based on inviscid dynamics and relates the failure and success of the inviscid theory to the relevance of viscous effects in the dynamics.