Controllability of the Navier-Stokes equation in a rectangle with a little help of a distributed phantom force

Jean-Michel Coron, Frédéric Marbach, Franck Sueur, Ping Zhang, Jean-Michel Coron, Frédéric Marbach, Franck Sueur, Ping, Jean-Michel Coron, Frédéric Marbach, Franck Sueur, Ping Zhang
2018 unpublished
We consider the 2D incompressible Navier-Stokes equation in a rectangle with the usual no-slip boundary condition prescribed on the upper and lower boundaries. We prove that for any positive time, for any finite energy initial data, there exist controls on the left and right boundaries and a distributed force, which can be chosen arbitrarily small in any Sobolev norm in space, such that the corresponding solution is at rest at the given final time. Our work improves earlier results in [17, 18]
more » ... here the distributed force is small only in a negative Sobolev space. It is a further step towards an answer to Jacques-Louis Lions' question in [23] about the small-time global exact boundary controllability of the Navier-Stokes equation with the no-slip boundary condition, for which no distributed force is allowed. Our analysis relies on the well-prepared dissipation method already used in [28] for Burgers and in [10] for Navier-Stokes in the case of the Navier slip-with-friction boundary condition. In order to handle the larger boundary layers associated with the no-slip boundary condition, we perform a preliminary regularization into analytic functions with arbitrarily large analytic radius and prove a long-time nonlin-ear Cauchy-Kovalevskaya estimate relying only on horizontal analyticity, in the spirit of [3, 35].
fatcat:sbkuzuo6i5h27bcrj3qp7s3z3q