Subgrid-scale modeling of enstrophy transfer in two-dimensional turbulence

Abstract

A method of parameterization of the energy and enstropy transfers involving subgrid scales is proposed in order to predict the time evolution of the energy spectrum at larger scales. The method is based on the strong non-localness of enstrophy transfer within the enstrophy inertial range of turbulence in two dimensions. It is applied first to a master equation derived from an eddy-damped quasi-normal Markovian model. Comparisons with reference calculations including all the scales up to the dissipation range show that the method simulates the enstrophy inertial range accurately up to the cutoff wavenumber. It is then generalized to direct simulation of the two-dimensional Navier-Stokes equation: the inertial range is again accurately simulated.