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Vortex dynamics of clapping plates

Kim, Daegyoum and Hussain, Fazle and Gharib, Morteza (2013) Vortex dynamics of clapping plates. Journal of Fluid Mechanics, 714 . pp. 5-23. ISSN 0022-1120.

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Vortex formation and force generation of clapping plates with various aspect ratios (AR) and stroke angles were investigated. Experiments were performed with a pair of hinged rectangular plates that were rotated symmetrically in a static fluid, and defocusing digital particle image velocimetry was employed to measure the three-dimensional flow field. Single-plate cases were also studied to compare with clapping plate cases. As AR decreases, both circulation of the tip vortex and area enclosed by the vortex loop increase inversely. An empirical power-law relationship with a negative exponent is found between total impulse and AR for a given stroke angle. The sensitivity of the force generated by the plates to the change of AR is larger at the smaller stroke angle because of faster acceleration and deceleration. The increase in impulse per plate from the single-plate case to the clapping double-plate case is larger for lower AR. These results reveal that low AR wings are more efficient in propulsive force generation in some specific modes of unsteady flapping flight. The evolution of the wake structures is found to depend on AR and stroke angle.

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Gharib, Morteza0000-0002-2204-9302
Additional Information:© 2013 Cambridge University Press. Received 16 November 2011; revised 18 August 2012; accepted 6 September 2012. Published online: 02 January 2013.
Subject Keywords:biological fluid dynamics, propulsion, swimming/flying, vortex dynamics, vortex flows
Record Number:CaltechAUTHORS:20130214-133249588
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Official Citation:Daegyoum Kim, Fazle Hussain and Morteza Gharib (2013). Vortex dynamics of clapping plates. Journal of Fluid Mechanics, 714, pp 5-23 doi:10.1017/jfm.2012.445
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36932
Deposited By: Tony Diaz
Deposited On:14 Feb 2013 22:59
Last Modified:03 Oct 2019 04:43

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