Competing states in a Couette-Taylor system with an axial flow

We present experimental results on novel pattern states which were observed in the Couette-Taylor flow subjected to an axial flow, in a wide range of the control parameters. Propagating Taylor vortices (PTV’s), stationary spirals (SSP’s), and moving spirals (MS’s) were found as a result of a different symmetry breaking. These modes exhibit different wave-number selection. Novel states originating from an interaction between these patterns were also found. A ‘‘mixed phase’’ of PTV’s and SSP’s was identified. A ‘‘mode-competition’’ state, in which the PTV’s and MS’s are alternated in the column, is also described. Finally, a ‘‘disordered-Taylor-vortices’’ state was observed and characterized.