Vanishing viscosity limit for global attractors for the damped Navier--Stokes system with stress free boundary conditions

We consider the damped and driven Navier--Stokes system with stress free boundary conditions and the damped Euler system in a bounded domain $\Omega\subset\mathbf{R}^2$. We show that the damped Euler system has a (strong) global attractor in~$H^1(\Omega)$. We also show that in the vanishing viscosity limit the global attractors of the Navier--Stokes system converge in the non-symmetric Hausdorff distance in $H^1(\Omega)$ to the the strong global attractor of the limiting damped Euler system (whose solutions are not necessarily unique).