Wavy Taylor vortex flow between eccentric rotating cylinders

The effect of eccentricity ratio on the appearance of Taylor vortices, the transition to wavy vortex flow, and subsequent changes in azimuthal wave-number in the flow between a rotating inner cylinder and a stationary outer cylinder was investigated by torque measurements and visual observations. The variation of the critical Taylor number with eccentricity ratio is almost independent of the radius ratio for eccentricity ratios less than 0.5; the transition to wavy vortex flow and the changes in azimuthal wave-number result in a temporary decrease in the rate of torque increase with speed. The Taylor numbers corresponding to these higher modes of instability are strongly dependent on the radius ratio.