Stabilité d'un écoulement de type Poiseuille Rayleigh-Bénard pour des fluides à seuil

National audienceA weakly non linear analysis is performed for the Poiseuille Rayleigh-Bénard flow involving a Bingham fluid. The material behaviour presents a yield stress. When the applied stress is less important than the yield stress then the material is like a gel. Above, the material behaves as a viscous fluid. In this study, we highlight a change in the bifurcation nature close to the value $Pe=O(1)$. This is the consequence of the high viscosity stratification in the yielded regions