It is not yet known if the global attractor of the space-periodic 2D Navier-Stokes equations contains non-stationary solutions u(x,t) such that their energy and enstrophy per unit mass are constant ...

The dissipative two dimensional Quasi-Geostrophic Equation (2D QGE) is studied. First, we prove existence and uniqueness of the solution, local in time, in the critical Sobolev space H2–2α with ...