The evolution of artificially generated localized disturbances having the shape of hairpins, in laminar axisymmetric rotating shear flows, is experimentally [1] and numerically investigated. The results are compared with the predictions of a theoretical model [2] with respect to the growth of such disturbances. Hairpin vortices were generated at the surface of the inner cylinder of an axisymmetric Couette apparatus, using suction through two holes. An instability domain, within the range of the basic flow parameters where the flow is known to be linearly stable, was found. The marginal ratio between the angular velocities of the inner and outer cylinders, beyond which the flow is table to finite-amplitude localized disturbances, agrees with theoretical prediction based on the measured mean flow in the region of the disturbance.
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