How flexibility affects the wake symmetry properties of a self-propelled plunging foil

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	How flexibility affects the wake symmetry properties of a self-propelled plunging foil
	Zhu XJ(朱晓珏); He GW(何国威); Zhang X(张星); Zhang X(张星)
发表期刊	Journal of Fluid Mechanics
	2014-07
卷号	751 页码:164-183.
ISSN	0022-1120
摘要	The wake symmetry properties of a flapping-foil system are closely associated with its propulsive performance. In the present work, the effect of the foil flexibility on the wake symmetry properties of a self-propelled plunging foil is studied numerically. We compare the wakes of a flexible foil and a rigid foil at a low flapping Reynolds number of 200. The two foils are of the same dimensions, flapping frequency, leading-edge amplitude and cruising velocity but different bending rigidities. The results indicate that flexibility can either inhibit or trigger the symmetry breaking of the wake. We find that there exists a threshold value of vortex circulation above which symmetry breaking occurs. The modification of vortex circulation is found to be the pivotal factor in the influence of the foil flexibility on the wake symmetry properties. An increase in flexibility can result in a reduction in the vorticity production at the leading edge because ofthe decrease in the effective angle of attack, but it also enhances vorticity production at the trailing edge because of the increase in the trailing-edge flapping velocity. The competition between these two opposing effects eventually determines the strength of vortex circulation, which, in turn, governs the wake symmetry properties. Further investigation indicates that the former effect is related to the streamlined shape of the deformed foil while the latter effect is associated with structural resonance. The results of this work provide new insights into the functional role of passive flexibility inflapping-based biolocomotion.
关键词	Flow-structure Interactions Propulsion Vortex Streets
学科领域	流体力学
URL	查看原文
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000337925000011
项目资助者	NSFC: 11021262, 11023001, 11232011,11372331. 973: 2013CB834100
课题组名称	LNM湍流
论文分区	一类
引用统计	被引频次：70[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/48856
专题	非线性力学国家重点实验室
通讯作者	Zhang X(张星)
推荐引用方式 GB/T 7714	Zhu XJ,He GW,Zhang X,et al. How flexibility affects the wake symmetry properties of a self-propelled plunging foil[J]. Journal of Fluid Mechanics,2014,751:164-183..
APA	Zhu XJ,He GW,Zhang X,&张星.(2014).How flexibility affects the wake symmetry properties of a self-propelled plunging foil.Journal of Fluid Mechanics,751,164-183..
MLA	Zhu XJ,et al."How flexibility affects the wake symmetry properties of a self-propelled plunging foil".Journal of Fluid Mechanics 751(2014):164-183..

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