Turbulent Spot in Linearly Stable Taylor Couette Flow

Abstract

The transition from the laminar to the turbulent regime in linearly stable shear flows, for example, pipe and plane Couette flows, occurs abruptly with no precursor. The evolution of turbulent spots has been studied to better understand the dynamics of this transition and the onset of turbulence. These studies have mostly focused on pipe flows for which a finite lifetime of spots was proven. The same conclusion was drawn in the only available study performed in a Taylor Couette setup. Here, the spot lifetime is measured in a different size TC setup. It is shown that the lifetime is indeed finite and also very sensitive to boundary conditions, but not much to perturbation mechanisms. A scaling approach is provided which suggests in addition to the Reynolds number, the aspect and radius ratios are influential parameters on the lifetime. It is found that the spot size varies during its lifetime and increases with the Reynolds number that confirms the rise in turbulence proliferation by approaching the transitional point.

Routes to turbulence in Taylor–Couette flow

“…This result, in qualitative agreement with previous studies of pipe flow [98,99], was confirmed by Alidai et al. [100], who additionally showed that τd does not depend on the specific details of how the turbulence is initially triggered, but is significantly affected by imperfections in the experimental apparatus, and by the end-wall conditions. Finally, they also showed that as Γ is reduced, τd decreases.…”