We propose a model for a medical device, called a stent, designed for
the treatment of cerebral aneurysms. The stent consists of a grid,
immersed in the blood flow and located at the inlet of the aneurysm.
It aims at promoting a clot within the aneurysm. The blood flow is
modelled by the incompressible Navier-Stokes equations and the stent
by a dissipative surface term. We propose a stabilized finite element
method for this model and we analyse its convergence in the case of
the Stokes equations. We present numerical results for academical test
cases, and on a realistic aneurysm obtained from medical imaging.