| 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)
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| Source Publication | Proceedings of the International Offshore and Polar Engineering Conference |
| 2021 | |
| Conference Name | 31st International Ocean and Polar Engineering Conference, ISOPE 2021 |
| Conference Date | 20 June 2021 到 25 June 2021 |
| Conference Place | Virtual, Online |
| Abstract | 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). |
| Keyword | Circular cylinder Particle Image Velocimetry (PIV) Shear flow Strouhal number Vortex shedding Wall proximity effects |
| Indexed By | EI |
| Language | 英语 |
| Document Type | 会议论文 |
| Identifier | http://dspace.imech.ac.cn/handle/311007/87799 |
| Collection | 流固耦合系统力学重点实验室 |
| Affiliation | 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 |
| Recommended Citation 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. |
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