Centrifugal instability of pulsed flow

The stability of a pulsed flow in a Taylor–Couette geometry with both cylinders rotating at the same angular velocity Ω(t)=Ω0 cos (ωt) is investigated. The first experimental evidence showing that the flow is less unstable in the limit of low and high frequency while destabilization is maximum for an intermediate frequency ω0 is reported. A detailed analysis of the restabilization at frequencies just above ω0 reveals a behavior not accounted for by previous theoretical analysis. Thus, the linear stability analysis is reconsidered by using a different implementation of the Floquet theory and a satisfactory agreement with the present experimental results is found.