FLOW IN THE HALF-FILLED ANNULUS BETWEEN HORIZONTAL CONCENTRIC CYLINDERS IN RELATIVE ROTATION

Experimental and theoretical results are presented for the flow in a half-filled annulus between horizontal concentric cylinders with the inner one rotating and the outer one at rest. A laser-Doppler velocimeter was used to measure the mean tangential and/or corresponding turbulent velocity distributions for both the laminar and turbulent regimes. Colour dyes were also used to visualize the flow patterns. The Reynolds number based on the gap width varied from 67 to 3242, which corresponds to a Taylor number ranging from 25 to 1200. From the graph of local moment coefficient versus Taylor number and the visualization results, laminar, transition and turbulent regimes are identified. In the analysis, the governing equations are expressed in stream-function and vorticity forms and expanded in terms of the power series of the annulus aspect ratio. The zero— and first-order solutions are then solved numerically. Various features of the flow, in particular the presence of vortices in the exit end region and their absence from the entry end region, predicted in the analysis, are confirmed by the experimental findings. © 1990, Cambridge University Press. All rights reserved.