Noise-Modulated Propagating Pattern in a Convectively Unstable System

A noise-sustained and noise-modulated structure of propagating Taylor vortices (PTV) in a convectively unstable regime of Couette-Taylor flow with a superimposed axial flow was observed and studied. The structure differs drastically from PTV in an absolutely unstable regime in its noisy power spectrum and in the noisy temporal dynamics of the front. Interaction of perturbations with the interface causes an amplitude modulation near the front and a noisy phase further to the outlet. The dependence of the front location on the control parameter indicates that perturbations from the inlet are responsible for the PTV existence.