Résumé
We investigate qualitative properties of strong solutions to a classical system describing the fall of it rigid hall under the action of gravity inside a bounded cavity filled with a viscous incompressible fluid. We prove contact between the ball and the boundary of the cavity implies blow up of strong solutions and such a contact has to Occur in finite time under symmetry assumptions on the initial data. (C) 2009 Elsevier Masson SAS. All rights reserved.