Optimal eddy viscosity in closure models for two-dimensional turbulent flows

We consider the question of fundamental limitations on the performance of eddy-viscosity closure models for turbulent flows, focusing on the Leith model for two-dimensional large-eddy simulation. Optimal eddy viscosities depending on the magnitude of the vorticity gradient are determined subject to minimum assumptions by solving PDE-constrained optimization problems defined such that the corresponding optimal large-eddy simulation best matches …