Primary and secondary Hopf bifurcations in stratified Taylor Couette flow.
Résumé
Experimental and theoretical results for the axially, stably stratified Taylor-Couette flow are presented. The primary instability is a direct Hopf bifurcation. It leads the system into an oscillatory state of confined internal waves, in good agreement with linear stability analysis. The secondary bifurcation, which leads the system to a pattern of drifting nonaxisymmetric vortices, is a subcritical Hopf bifurcation. This first experimental evidence of a global bifurcation is thought to be generic to dynamical systems with one destabilizing and one stabilizing control parameter.