Thermosolutal bifurcation phenomena in a rectangular enclosure filled with non –Newtonian fluids

Résumé

This paper reports an analytical and numerical study of double-diffusive natural convection in a non-Newtonian power-law fluid contained in a horizontal rectangular enclosure submitted to uniform heat and mass fluxes along its short vertical sides, while the horizontal ones are insulated and impermeable. An analytical model, based on the parallel flow approximation, is proposed for the case of a shallow layer (A>>1). The particular case where the thermal buoyancy forces are dominating the flow (N = -0.98) is considered. For this situation the two saddle-nodes bifurcation are predicted. The study is completed by a numerical solution of the full governing equations.