Didier Bresch (Université Savoie Mont-Blanc)

In this talk, we will show the importance to increase artificially the number of unknowns for some PDEs in fluid mechanics to treat some theoretical and numerical problems: existence, stability and singular perturbations will be dicussed and the practical utility for certain environmental or industrial applications will be illustrated. From a physical point of view, for some problems we will talk about, this could be understood as two velocity hydrodynamics for heterogeneous flows even if a priori there exists only one velocity field.