1A Closed-Form Feedback Controller for Stabilization of the Linearized 2-D

Abstract—We present a formula for a boundary control law which stabilizes the parabolic profile of an infinite channel flow, which is linearly unstable for high Reynolds numbers. Also known as the Poisseuille flow, this problem is frequently cited as a paradigm for transition to turbulence, whose stabilization for arbitrary Reynolds numbers, without using discretization, has so far been an open problem. Our result achieves exponential stability in the L2, H1 and H2 norms, for the linearized Navier-Stokes equations. Explicit solutions are obtained for the closed loop system. This is the first time explicit formulae are produced for solutions of the linearized Navier-Stokes equations in a channel flow, with feedback in the boundary conditions used to make this possible. The result is presented for the 2D case for clarity of exposition. An extension to 3D is available and will be presented in a future publication. Index Terms—Flow control, Navier-Stokes equations, back-stepping, boundary control, distributed parameter systems, Lya