Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2183
標題: 下游圓柱加設隔板對縱列雙圓柱間自激式震盪特性的影響
Influence of Downstream Flat plate on Self-Excited Oscillation between Two Tandem Cylinders
作者: 鄭大瑋
Cheng, Ta-Wei
關鍵字: Tandem cylinders;縱列圓柱;self-excited;flat olate;wavelettransformation;自激式震盪;隔板;小波分析
出版社: 機械工程學系所
引用: 1. Alam M.M. ,Zhou Y.,“Phase Lag between Vortex Shedding from Two Tandem Bluff Bodies”,Journal of Fluids and Structures, 2007, Vol.23, pp. 339~347. 2. Alam M.M. ,Moriya M. ,Takai K. ,Sakamoto H.,“Fluctuating Fluid Forces Acting on Two Circular cylinders in a Tandem Arrangement at a Subcritical Reynolds Number ”,Journal of Wind Engineering and Industrial Aerodynamics, 2003, Vol. 91, pp. 139~154. 3. Alam M.M. ,Sakamoto H. ,Moriya M.,“Reduction of Fluid Fprces Acting on a Single Circular Cylinder and Two Circular Cylinders by Using Tripping Rods ”,Journal of Fluids and Structures, 2003, Vol.18,pp.347~366. 4. Alam M.M. ,Zhou Y.,“Strouhal Numbers,Forces and Flow Structures around Two Tandem Cylinders of Different Diameters”,Journal of Fluids and Structures, 2008, Vol.24,pp.505~526. 5. Carmo B.S. ,Meneghini J.R.,“Numerical Investigation of Flow around Two Circular Cylinders in Tandem”,Journal of Fluids and Structures, 2006, Vol.22,pp.979~988. 6. Kuo C.H. ,Chein S.M. ,Hsieh H.J.,“Self-Sustained Oscillations between Two Tandem Cylinders at Reynolds Number 1000”,Journal of Experiment in Fluids, 2008, Vol.44,pp.503~517. 7. Lin J.-C. ,Yang Y. and Rockwell D.,“Flow Past Two Cylinders In Tandem:Instantaneous And Averaged Flow Structure”,Journal of Fluids and Structures, 2002, Vol.16,N0.8,pp.1059~1071. 8. Ozono S.“Flow Control of Vortex Shedding by a Short Splitter Plate Asymmetrically Arranged Downstream of Cylinder”,Physics of Fluids, 1999, Vol.11,No.10,pp.2928~2934. 9. Sharman B. ,Lien F.S. ,Davidson L. and Norberg C.,“Numerical Predictions of Low Reynolds Number Flows over Two Tandem Circular Cylinders”,international Journal for Numerical Methods In Fluids, 2005, Vol.47,pp.423~447. 10. Sumner D. ,Price J.S. and Paidoussis M.P.,“Tandem Cylinders In Impulsively Started Flow”,Journal of Fluids and Structures, 1999, Vol.13,pp.955~965. 11. Xiu G. ,Zhou Y.,“Strouhal Numbers in the Wake of Two Inline Cylinders”,Journal of Experiment in Fluids, 2004, Vol.37,pp.248~256. 12. Zdravkovich M.M.,“Review of Interference-Induced Oscillations in Flow Past Two Parallel Circular Cylinders in Various Arrangements”,Journal of Wind Engineering and Industrial Aerodynamics, 1988, Vol.28,pp.183~200. 13. 林威宇,“均勻流場中旋轉圓柱尾流特性之探討”,國立中興大學機械研究所碩士論文,1999。
摘要: 
本文研究主旨是探討當雷諾數為1000時,具相同直徑之縱列雙圓柱的下游圓柱後沿著流向放置隔板,對縱列雙圓柱間的流場結構之影響。在定性方面是以螢光染料釋放法來作流場可視化,來觀察下游圓柱尾流的流場結構,以及雙圓柱間流場結構變化。定量方面,是以LDV系統來作流場的定量量測;再配合PIV系統量測處理後的瞬間渦度分布圖來了解瞬間的流場特性。
本研究結果顯示:(1)當雙圓柱中心間距L/D=3.5~L/D=4.0時,雙圓柱間流場出現自激式震盪的特性。(2)當雙圓柱中心間距L/D=4.5~L/D=5.5時,雙圓柱間的流場結構為自激式震盪的流場特性。(3)當雙圓柱中心間距L/D=6.0時,雙圓柱間流場特性具有交替渦漩脫離以及對稱渦漩的不定時轉換特性。而與下游圓柱後未放置隔板比較發現:當雙圓柱中心間距L/D=3.5~L/D=4.0時,由平順剪力層結構轉變為自激式震盪特性。當雙圓柱中心間距L/D=4.5~L/D=5.5時,雙圓柱間所量測得的特徵頻率略高於下游圓柱後無放至隔板者。當雙圓柱中心間距L/D=6.0時,雙圓柱間流場特性由交替脫離渦漩結構轉變為不定時轉換特性。

This study focus on the influence of a flat plate, placed behind the downstream cylinder on the self-excited oscillation between two tandem circular cylinders of equal diameter when the Reynolds number was 1000. All experiments were performed in a recirculating water channel. The qualitative flow visualization was couducted by the laser sheet technique. The quantitative velocity measured were using the LDV and the PIV systems.
It is found that the flow characteristics between two cylinders is a self-excited oscillation as the center-to-center spacing is L/D=3.5~5.5.
The flow between two cylinders changes imtermittently when the center-to-center spacing L/D=6.0.
Compared with the results without plate located behind the downstream cylinder.the range of center-to-center spacing of the self-excited oscillations are found to extend wide in both directions .Namely, extensive with L/D=3.5~4.0 and L/D=5.5.Further, the characteristics frequency measured between tandem cylinder is slightly higher than those of without that plate.
URI: http://hdl.handle.net/11455/2183
其他識別: U0005-2708200817302700
Appears in Collections:機械工程學系所

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