The flow between a rotating lid and a stationary cylinder is studied experimentally. The flow is governed by two parameters: The ratio of container height to disk radius, h, and the Reynolds number, Re, based on the disk angular velocity, cylinder radius and kinematic viscosity of the working liquid. For the first time the onset of three-dimensionality and transition are analysed by combining the high spatial resolution of Particle Image Velocimetry (PIV) and the temporal accuracy of Laser Doppler Anemometry (LDA). A detailed mapping of the transition from steady and axisymmetric flow to unsteady and non-axisymmetric flow is investigated for 1 <h <3.5. The flow is characterized by the azimuthal wave number and associated characteristic frequencies. A range of different modes is detected and critical Reynolds numbers and frequencies identified. The results are compared to the numerical stability analysis of Gelfgat et al. [J. Fluid. Mech. 438, (2001)]. In most cases the measured onset of three-dimensionality is in good agreement with the numerical results and disagreements can be explained by bifurcations not accounted for by the stability analysis.
|Journal||Experiments in Fluids|
|Publication status||Published - 2006|