| Abstract: | Turbulent Taylor vortices between two concentric cylinders have been studied at a very high radius ratio of 0.985, equivalent to that found in relatively small underwater thruster units (typically with gaps of 2 mm). In order to study the flow at this radius ratio, a 1.42-m diameter experimental apparatus (with a rotating inner cylinder and a stationary outer cylinder) was constructed possessing a gap of 10 mm. Consequently, air bubbles could be visualised translating in water. A method was developed for identifying Taylor vortex properties from filtered digital images of the air bubbles and summing intensities to produce bubble density distributions. Whereas individual instantaneous images can be misleading, averaged bubble density distributions make it possible to identify vortex separation sizes and the positions of vortex outflow boundaries. |
