The Effects of Rotation on Finite-Amplitude Perturbation Thresholds for Transition in Subcritical Taylor-Couette Flow

While famous for its transition to turbulence via a hierarchy of centrifugal instabilities of ever increasing complexity, Taylor-Couette flow (i.e., the flow between independently rotating cylinders) can also bypass linear instabilities and become turbulent via a subcritical route. In this case, the laminar state is linearly stable but sufficiently large finite-amplitude perturbations can destabilize it and cause the system to jump directly to a state with a high degree of spatiotemporal complexity. Here, we present some preliminary results regarding the effects of rotation on the minimum perturbation strength required to trigger turbulence. The perturbations are introduced by small jet emanating from the inner cylinder wall. By differentially rotating the cylinders and probing the systems with jets of different strengths, we can separate the influence of rotation from that of pure shear on the stability of the flow, as proposed by Dubrulle et al. (Phys. Fluids 17, 095103 (2005)). Our preliminary results suggest that rotation can have a strong effect on the stability of Taylor-Couette flow to finite-amplitude perturbations depending on experimental conditions.