Speaker: Professor Frederic Marbach
From: University of Rennes, France
Title : Controllability despite boundary layers
Time: 3:00-5:00, May 4
Place: Room 913, South Building

Abstract : Controllability is the question of whether one can find a
source-term (the control) to drive the solution of an evolution equation
from a given initial state to a prescribed final state. In this lecture,
we will study the question of controllability in small time for systems
coming from fluid mechanics (Burgers, Navier-Stokes). I will explain why
answering this question implies understanding the behavior of boundary
layers. Several usual techniques will be used: asymptotic expansions,
Coron's return method, energy estimates (Sobolev or analytic). I will also
explain a recent technique to build controls that enhance the dissipation
of the involved boundary layers.