Wall-proximity effects on strouhal number for the circular cylinder in a shear flow

IMECH-IR > 流固耦合系统力学重点实验室

	Wall-proximity effects on strouhal number for the circular cylinder in a shear flow
	Liu Y(刘艳); Liu J(刘俊); Gao FP(高福平)
会议录名称	Proceedings of the International Offshore and Polar Engineering Conference
	2021
会议名称	31st International Ocean and Polar Engineering Conference, ISOPE 2021
会议日期	20 June 2021 到 25 June 2021
会议地点	Virtual, Online
摘要	Strouhal number is an essential dimensionless quantity for characterizing the vortex shedding frequency of the flow around a bluff body. In this study, the Strouhal number for a near-wall circular cylinder fully immerged in a shear flow was experimentally investigated within the subcritical Reynolds number range. The examined gap-to-diameter ratios (e/D) are in the range of 0.10 ~ 2.0. The velocity fluctuations of the lee-wake and the flow visualization were measured with an Acoustic Doppler Velocimeter and the Particle Image Velocimetry system, respectively. The wall-proximity effects on the vortex shedding and the corresponding Strouhal number (St) were investigated experimentally. Although the regular Kármán-like vortex-shedding can be suppressed for e/D 0.30, the power spectra for the velocity fluctuations in the lee-wake indicate that the characteristic frequency can still be well identified. The experimental results indicate that St increases with the decrease of e/D to a maximum value at e/D = 0.40; and the maximum of St is approximately 15 percent larger than that under wall-free condition. Broadband spectrum phenomenon was observed under the very-small e/D conditions (i.e., e/D 0.20). The shear parameter (K) of the shear flow is proposed, and its explicit expression is derived for characterizing the wall-proximity. The relationship between the Strouhal number St and e/D (or K) is finally established for 0.10 e/D 2.0. © 2021 by the International Society of Offshore and Polar Engineers (ISOPE).
关键词	Circular cylinder Particle Image Velocimetry (PIV) Shear flow Strouhal number Vortex shedding Wall proximity effects
收录类别	EI
语种	英语
文献类型	会议论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/87799
专题	流固耦合系统力学重点实验室
作者单位	1.Key Laboratory for Mechanics in Fluid Solid Coupling Systems, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China 2.School of Engineering Science, University of Chinese Academy of Sciences, Beijing, China
推荐引用方式 GB/T 7714	Liu Y,Liu J,Gao FP. Wall-proximity effects on strouhal number for the circular cylinder in a shear flow[C]Proceedings of the International Offshore and Polar Engineering Conference,2021.