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Experimental investigation of flow development and gap vortex street in an eccentric annular channel. Part 1. Overview of the flow structure

Published online by Cambridge University Press:  09 July 2014

George H. Choueiri
Affiliation:
Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, Canada K1N 6N5
Stavros Tavoularis*
Affiliation:
Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, Canada K1N 6N5
*
Email address for correspondence: stavros.tavoularis@uottawa.ca

Abstract

Flow visualization, laser Doppler velocimetry and planar and stereoscopic particle image velocimetry were used to investigate the isothermal velocity field along an eccentric annular channel with a diameter ratio of 0.5 and an eccentricity of 0.8 for a Reynolds number of 7300. Observation of the flow development has identified three distinct regions: the entrance region, the fluctuation-growth (FG) region and the rapid-mixing (RM) region. Weak quasi-periodic velocity fluctuations were first detected in the downstream part of the entrance region, and grew into very strong ones, reaching peak-to-peak amplitudes in the narrow gap that were nearly 60 % of the bulk velocity. Two mixing layers were identified on either side of the gap, which generated a street of counter rotating vortices and thorough large-scale mixing of the fluid in the channel.

Type
Papers
Copyright
© 2014 Cambridge University Press 

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Choueiri and Tavoularis supplementary movie

Flow visualization showing the development of a gap vortex street in an eccentric annular channel having a diameter ratio of 0.5 and an eccentricity of 0.8. The camera was traversed slowly from the inlet to the outlet of the channel.

Download Choueiri and Tavoularis supplementary movie(Video)
Video 3.7 MB