Comparison of computations of asymptotic flow models in a constricted channel.

We aim at comparing computations with asymptotic models issued from incom-pressible Navier-Stokes at high Reynolds number: the Reduced Navier-Stokes/Prandtl (RNS/P) equations and the Double Deck (DD) equations. We treat the case of the steady two dimensional flow in a constricted pipe. In particular, finite differences and finite element solvers are compared for the RNS/P equations. It results from this study that the two codes compare well. Numerical examples also illustrate the interest of these asymptotic models as well as the flexibility of the finite element solver.