Experiments on Wave Number Selection in Rotating Couette-Taylor Flow

Experimental results are reported for the selection of axial wavelengths of Taylor vortices in a system where the Reynolds number, $R$, is "ramped" spatially from above to below the critical value, $R_c$, for the onset of vortex flow. It is found that a sufficiently slow ramp connecting the supercritical region (containing vortices) to a subcritical region (of purely azimuthal flow) results in the selection of a unique wavelength. A more rapid ramp results in a small $R$-dependent band of allowed wavelengths which grows in width as $R\to R_c$ from above.