Experimental investigation of the flow-induced vibration of a curved circular cylinder

Assi, Gustavo and Freire, Cesar and Korkischko, Ivan and Srinil, Narakorn; Meskell, C. and Bennett, G., eds. (2012) Experimental investigation of the flow-induced vibration of a curved circular cylinder. In: Proceedings of the 10th International conference on Flow-Induced Vibration (& Flow-Induce Noise). Trinity College Dublin, IRL, pp. 543-554. ISBN 978-0-9548583-4-6

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Abstract

Experiments have been conducted to investigate the vortex-induced vibration (VIV) response of a rigid section of a curved circular cylinder. Two curved configurations, a concave and a convex, were tested regarding the direction of the flow, in addition to a straight cylinder that served as reference. Amplitude and frequency response are presented versus reduced velocity for a Reynolds number range between 750 and 15,000. Results showed that the curved cylinders presented significant less vibration for both concave and convex configurations when compared to the typical VIV response of a straight cylinder. The concave configuration presented relatively high amplitudes of vibration that are sustained beyond the typical synchronisation region. We believe this distinct behaviour between the convex and the concave configurations is related to the wake interference happening in the lower half of the curvature due to perturbations generated in the horizontal section when it is positioned upstream. Particle-image velocimetry (PIV) measurements of the separated flow along the cylinder highlight the effect of curvature on vortex formation and excitation revealing a complex fluid-structure interaction mechanism.