Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/1716
標題: 縱列雙鈍體間自激式流場之實驗探討
Experimental Investigation on Self-Excited Flow between Two Tandem Bluff Bodies
作者: 謝宏杰
Hsieh, Hung-Chieh
關鍵字: tandem;縱列;bluff body;self-excited;Wavelet transformation;鈍體;自激式振盪;小波分析法
出版社: 機械工程學系所
引用: 參 考 文 獻 1. Gu, Z., “on Interference between Two Circular Cylinders at Supercritical Reynolds Numbers”, Journal of Wind Engineering and Industrial Aerodynamics, 1996, Vol. 62, pp.175-190。 2. Jeste, W. and Kallinderis, Y., “Numerical Study of Incompressible Flow about Fixed Cylinder Pairs”, Journal of Fluids and Structures, 2003, Vol. 17, pp.561-577。 3.Lin, C., Hsieh, S.C., Chang, K.T., “The Formation Length and Convection Velocity of Vortex Structure in The Near Wake of A Circular Cylind”, Proceedings of The Fifth International Conference on Hydrodynamics , 2002, pp.245-249。 4. Mittal, S., Kumar, V., Raghuvanshi, A., “Unsteady Incompressible Flows Past Two Cylinders in Tandem and Staggered Arrangements”, International Journal for Numerical Methods in Fluids, 1997, Vol. 25, pp.1315 ~ 1344。 5. Ozono, S., “ Vortex Suppression of The Cylinder Wake by Deflectors”, Journal of Wind Engineering and Industrial Aerodynamics, 2003, Vol. 91, pp.91~99。 6. Ozono, S., “Flow Control of Vortex Shedding by A Short Splitter Plate Asymmetrically Arranged Downstream of A Cylinder”, Physics of Fluids, 1999, Vol. 11, No. 10, pp. 2928~2934。 7. Sakamoto, H. and Alam Mahbub, Md., “Investigation of Strouhal Frequencies of Two Staggered Bluff Bodies and Detection of Multisable Flow by Wavelets”, Journal of Fluids and Structures, 2005, Vol. 20, pp.425-449。 8. Sakamoto, H., Alam Mahbub, Md., Moriya, M., Takai, K., “Fluctuating Fluid Forces Acting on Two Circular Cylinders in A Tandem Arrangement at A SubcriticalReynolds Number”, Journal of Wind Engineering and Industrial Aerodynamics, 2003, Vol. 91, pp.139 ~154。 9. Sharman, B., Lien, F. S., Davidson, L., Norberg, C., “Numerical Predictions of Low Reynolds Number Fows over Two Tandem Circular Cylinders”, International Journal for Numerical Methods in Fluids, 2005, Vol. 47, pp.423 ~ 447。 10. Sumner, D., Price, S. J., Paidoussis, M. P., “Flow-Pattern Identification for Two Staggered Circular Cylinders in Cross-Flow”, Journal of Fluid Mechanics, 2000, Vol. 411, pp.263-303。 11. Sumner, D. and Richards, M.D., “Some Vortex-Shedding Characteristics of The Staggered Configuration of Circular Cylinders”, Journal of Fluids and Structures, 2003, Vol. 17, pp.345-350。 12. Sumner, D. and Akoile, O.O., “Staggered Circular Cylinders Immersed in A Uniform Planar Shear Flow”, Journal of Fluids and Structures, 2003, Vol. 18, pp.613-633。 13. Sumner, D., Richards, M.D., Akoile, O.O., “Two Staggered Circular Cylinders of Equal Dimeter in Cross-Flow”, Journal of Fluids and Structures, 2005, Vol. 20, pp. 255-276。 14. 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。 15.簡賢明, “縱列與錯列雙圓柱尾流結構之實驗分析”, 國立中興大學, 機械工程研究所碩士論文, 2002。 16.陳信安, “以小波方法分析並列雙圓柱尾流場所定特性”, 國立中興大學機械研究所碩士論文, 2004。 17.陳建章, “雙控制圓柱對於主要圓柱尾流幹擾之數值研究”, 國立中興大學, 機械工程研究所碩士論文, 2005。
摘要: 
摘 要
本文主旨在於研究入流的雷諾數為1000與2000,且雙鈍體具有不同排列方式與不同縱向間距時,雙鈍體間具有自激式振盪的流場特性。本研究之實驗是在低速循環迴路水槽中進行,流場可視化是以螢光染液釋放法進行,先定性的觀察縱列雙圓柱間流場結構的變化。定量方面,則使用雷射都卜勒測速儀搭配熱膜測速儀進行同步的定量流場量測,再將速度訊號以小波法分析,藉以瞭解雙鈍體間瞬時頻率變化。最後利用質點影像測速儀進行上游鈍體之渦漩形成長度與雙鈍體間平均渦度等之量測,藉以瞭解雙鈍體間自激式振盪形成的機制。
本實驗結果顯示:(1)雙鈍體間具有自激式振盪的流場特性歸納如下:雷諾數、雙鈍體間的縱向間距、上游鈍體的渦漩形成長度、下游鈍體相對之特徵尺寸等均是影響雙鈍體間自激式振盪特性的重要參數。(2)不同雙鈍體間可能的流場結構包括:平順剪力層流場結構、自激式振盪流場特性、各自獨立交替脫離渦漩結構,以及不定時交互轉換的流場,產生單一個自激式振盪,或兩種以上的特徵頻率來回跳動著,此時為不定時轉換過程的現象。(3)在簡【15】的研究中已經發現雙鈍體間具有自激式振盪的流場,但並未深入探討此流場特性,經本研究持續探討發現雙鈍體間的自激式振盪是一種持續且穩定存在的特性。

Abstract
This study investigates the self-excited flow characteristics between two tandem bluff bodies with different bluff body arrangements and various streamwise spacings. The Reynolds numbers studied are 1000 and 2000. The experiments are performed in a low-speed recirculation water channel. Qualitative flow structures were observed by the dye flow visualization, and the quantitative velocity measurements were performed by the PIV technique and the FLDV system, respectively. The phase information are calculated from two simultaneously measured velocity signals from FLDV and hot-film anemometer and are analyzed by cross Wavelet transformation. Further, utilizing particle image velocimetry system acquires the instantaneous and the average voritcity distribution of the self-excited flow structures between two
tandem bluff bodies.
It is found that: (1)occurrence of the self-excited flow between two tandem bluff bodies depend strongly upon: the Reynolds number, the streamwise spacing between two tandem bluff bodies, the vortex formation length of the single upstream bluff body, and the characteristic length of the downstream bluff body.(2)The flow characteristics between two bluff bodies includes smooth separated shear layer across the downstrem bluff body, the sustained self-excited flow, one vortex streets, and an intermittently changing flow characteristics between the self-excited flow structure and the shedding vortex street.(3)The self-excited flow characteristics is found between two bluff bodies, but the details are never discussed. The experiment finds the self-excited flow characteristics between two bluff bodies is a stable sustained
self-excited oscillatory flow structure.
URI: http://hdl.handle.net/11455/1716
其他識別: U0005-2601200712273300
Appears in Collections:機械工程學系所

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