“…The Oseen linearization as a base for controller design for the incompressible Navier-Stokes equations has been thoroughly analyzed as, e.g., in [22,27,29] for Dirichlet boundary control in two and three dimensions and with mixed boundary conditions, in [1] in two and three dimensions including space discretizations and Riccati-based state feedback, in [16] in view of observer design, in [26] with extension methods for the Dirichlet control, and in the textbook [2] with fundamental results on spectral properties. As for robust control, the Oseen linearization has been investigated in [2,12] in view of the operator H ∞ -Riccati equations. Separately, the need and applicability for H ∞ -robust controllers to account for discretization or linearization errors in flow control setups have been discussed in [4,5].…”