Résumé : In this talk, I will present a recent study on traveling waves solutions to a 1D biphasic Navier-Stokes system coupling compressible and incompressible phases. With this original fluid equations, we intend to model congestion (or saturation) phenomena in heterogeneous flows (mixtures, collective motion, etc.). I will first exhibit explicit partially congested propagation fronts and show that these solutions can be approached by profiles which are solutions to a singular compressible Navier-Stokes system. The last part of the talk will be dedicated to the analysis of the stability of the approximate profiles. This is a joint work with Anne-Laure Dalibard.

Keywords : compressible Navier-Stokes equations; singular limit; free boundary problem