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A study of two-dimensional flow past an oscillating cylinder

Blackburn, H. M. and Henderson, R. D. (1999) A study of two-dimensional flow past an oscillating cylinder. Journal of Fluid Mechanics, 385 . pp. 255-286. ISSN 0022-1120. http://resolver.caltech.edu/CaltechAUTHORS:BLAjfm99

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Abstract

In this paper we describe a detailed study of the wake structures and flow dynamics associated with simulated two-dimensional flows past a circular cylinder that is either stationary or in simple harmonic cross-flow oscillation. Results are examined for Re = 500 and a fixed motion amplitude of y(max)/D = 0.25. The study concentrates on a domain of oscillation frequencies near the natural shedding frequency of the fixed cylinder. In addition to the change in phase of vortex shedding with respect to cylinder motion observed in previous experimental studies, we note a central band of frequencies for which the wake exhibits long-time-scale relaxation oscillator behaviour. Time-periodic states with asymmetric wake structures and non-zero mean lift were also observed for oscillation frequencies near the lower edge of the relaxation oscillator band. In this regime we compute a number of bifurcations between different wake configurations and show that the flow state is not a unique function of the oscillation frequency. Results are interpreted using an analysis of vorticity generation and transport in the base region of the cylinder. We suggest that the dynamics of the change in phase of shedding arise from a competition between two different mechanisms of vorticity production.


Item Type:Article
Additional Information:"Reprinted with the permission of Cambridge University Press." Received 6 January 1998 and in revised form 12 November 1998. Published Online 8 September 2000. A significant proportion of the simulations reported here was performed at the Australian National University Supercomputer Facility, and we thank its staff for their support and assistance.
Subject Keywords:VERY-LOW MASS; CIRCULAR-CYLINDER; VORTEX FORMATION; TURBULENT FLOWS; WAKE; DYNAMICS; SIMULATION; VIBRATION; FORCES
Record Number:CaltechAUTHORS:BLAjfm99
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:BLAjfm99
Alternative URL:http://www.journals.cambridge.org/action/displayAbstract?fromPage=online&aid=15051
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2100
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Mar 2006
Last Modified:26 Dec 2012 08:47

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