Investigation of the effect of acceleration on Taylor vortex flow using MCCDPIV

The flow between two rotating concentric cylinders, known as Taylor-Couette flow, has long been the subject of theoretical and experimental investigation. As the rotational speed of the inner cylinder is slowly increased from rest, the laminar axisymmetric flow, also known as Couette flow, becomes un-stable. Coles (1965) was the first to show that the final state of the flow is strongly dependent on the initial conditions and the acceleration of the inner cylinder. For a given Reynolds number, as many as 20–25 different states can be identified. As the speed changes, these states replace each other in a re-peatable, but irreversible, pattern of transitions. When the inner cylinder is accelerated from rest a series of flow transitions with the following modes occurs: circular Couette flow (CCF) → Taylor vortex flow (TVF) → wavy vortex flow (WVF) → modulated wavy vortex flow (MWVF) → and turbulent Taylor vortex flow (TTVF). Lim, Chew & Xiao (1998) have shown that when the ratio η of the inner cylinder radius R1 to the outer cylinder radius R2 is 0.803 and the rate of change of Reynolds number is less than 2.2 secs−1, the standard transition sequence of CCF → TVF → WVF exists. However, when the acceleration of the flow is higher, the final state of the flow resembles a regular Taylor vortex flow, but has a shorter axial wavelength. Further work ([7]) has shown that this ”second Taylor vortex flow