Metastability and rapid convergence to quasi-stationary bar states for the two-dimensional Navier-Stokes equations (Q2871076)

This interesting paper is an attempt to describe the quasi-stationary (metastable) states occuring in the case of the 2D turbulent flows with small viscosity on the torus. These states decay on the slow viscous timescale. Approximation, by dropping a higher-order non-local term, of the time-dependent operator obtained by linearization about the quasi-stationary states, produces a decay rate much faster than the viscous decay rate. Numerical results are presented in the case of the full linear operator to illustrate the optimality of the theoretical decay rate in this setting.