流過一對並列橢圓柱同相位/異相位渦旋逸出流場之次臨界分歧過程研究

Hysteresis in anti-phase/in-phase synchronized vortex shedding forms of flows past a pair of side-by-side elliptic cylinders

鄭豐笙(Feng-Sheng Cheng)

指導教授 ： 彭逸凡

國立暨南國際大學/科技學院/土木工程學系/碩士(2013年)

https://doi.org/10.6837/NCNU.2013.00267

摘要

本文以數值分析方法探討於流過一對並列橢圓柱後方尾流的分歧過程，我們可以在之前相關論文中發現尾流流況是受到了G(間隙比)、Re(雷諾數)的影響，本文使用較小的Re數(Re<160)以及中間值的G(2.0

關鍵字

同相位 ； 異相位

並列摘要

Transition of flow past a pair of side-by-side elliptic cylinders with aspect ratio A=2 is investigated by numerical simulations and the bifurcation analysis of the numerical results. It is already known that flows past a pair of elliptical cylinders are influenced by the gap ratio G and Reynolds number Re. Various flow patterns behind the ellipses have been found and the transition diagram from steady to semi-single/twin symmetric/deflected vortex shedding flows have been reported in our previous study (Peng et. al.1). This study focus on transition of in-phase/anti-phase vortex shedding synchronized forms. It is found that the in-phase and anti-phase vortex shedding flows can co-exist at 2.26≦G≦2.58. Hysteresis loops with increasing/decreasing G at constant Reynolds number Re=100 and with increasing/decreasing Re at constant gap ratio G=2.4 are reported, respectively. The hysteresis phenomenon of in-phase/anti-phase vortex shedding synchronized forms is also investigated in flows past a pair of circular cylinders.

Keywords:anti-phase/in-phase

並列關鍵字

in-phase ； anti-phase

參考文獻

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