臺灣博碩士論文加值系統

　　本研究乃是藉由水工模擬的方式進行「瞬間起動球體流場之研究」，並利用雷射切頁法及雷射激發光化學量測法作流場之顯影觀察，實驗雷諾數範圍從100到3114。為了確信流場具有二維對稱的特性，吾人亦進行二維性之檢驗及誤差值級的分析。
　　文中詳盡介紹了實驗的進行方式、模型的加工及架設方法。在本實驗中利用鋼線將球體固定在流體中進行拖曳，然而三維物體之固定方式很可能影響實驗的結果，為了考量架設方法所可能導致對實驗結果的影響，吾人使用了不同尺寸的支撐線徑比例對實驗結果進行評估，初步發現在本實驗設定的線徑比例範圍以下對於尾流場的發展並不會造成明顯的干擾。
　　此外，文中亦包含在相同以及不同雷諾數下，尾流區域發展變化的趨勢研究，並對該區域的特徵尺度加以製圖分析，以期更進一步了解造成此一趨勢的物理因素。實驗結果亦包含與歷年文獻中臨界雷諾數以及不穩定因素所造成之影響部份進行比對及分析，實驗結果發現在臨界雷諾數217到270之間，尾流區域會明顯的失去steady的特性，尾流對稱發展的趨勢會隨著雷諾數的變化而產生驟降的趨勢。
　　除此之外，由於「邊界效應」對實驗結果的影響甚遠，吾人亦利用不同比例的『球』與『邊界』尺寸來加以分析測試段邊界是如何對尾流區域之發展產生『抑制』的效應，並將實驗結果與歷年文獻進行比對，並討論分析可能造成此一趨勢的次要因素，以期作為日後實驗進行方面的依歸。

摘要……………………………………………………………………I
目錄……………………………………………………………………II
圖表目錄………………………………………………………………IV
符號說明………………………………………………………………VI
第一章導論……………………………………………………………1
1.1 研究動機和目的………………………………………………1
1.2 文獻回顧………………………………………………………3
第二章實驗設備及實驗方法…………………………………………10
2.1 實驗水槽及拖曳式平台………………………………………10
2.2 實驗模型及架設………………………………………………11
2.3 工作流體及顯像技術…………………………………………13
2.3.1 工作流體……………………………………………13
2.3.2 氬離子雷射－雷射切頁法…………………………14
2.3.3 脈衝式雷射－雷射激光化學量測法………………16
2.4 影像之記錄與數據之拮取……………………………………18
2.4.1 取像設備……………………………………………18
2.4.2 數據拮取設備………………………………………19
2.5 實驗控制方法與流程…………………………………………19
第三章 校準與誤差分析………………………………………………23
3.1 照相機（Nikon F3）與MD-4自動捲片器…………………23
3.1.1 取像控制流程的誤差估計…………………………...23
3.1.2 快門誤差的估計……………………………………25
3.1.3 MD-4自動捲片器的影響…………………………..25
3.1.4 照片幾何長度的校準………………………………...26
3.2 平台瞬間起動誤差校準………………………………………27
3.3 雷諾數誤差分析………………………………………………28
第四章 結果與討論……………………………………………………30
4.1 座標定義與無因次方法………………………………………30
4.2 流場二維性的檢驗……………………………………………31
4.3 流場觀察………………………………………………………33
4.3.1 主渦漩………………………………………………33
4.3.2 次渦漩………………………………………………34
4.4 實驗流場觀察分析……………………………………………35
4.4.1 相同雷諾數之間的流場特性………………………35
4.4.2 不冋雷諾數之流場特性…………………………….36
4.5 實驗重覆性檢驗………………………………………………40
4.6 邊界條件與穩定性分析………………………………………41
4.6.1 線徑及邊界條件的影響……………………………..42
4.6.2 穩定週期探討……………………………………….45
4.7 實驗結果與數值方法之比較……………………………….47
4.7.1 數值方法之結果……………………………………..47
4.7.2 實驗與數值比較……………………………………..47
4.8 綜合比較………………………………………………………48
第五章 結論與未來展望………………………………………………51
5.1 結論………………………………………………………….51
5.2 未來展望……………………………………………………52
參考文獻………………………………………………………………53
圖表

ACHENBACH, E. 1974 Vortex Shedding from spheres. J. Fluid Mechanics 62, 209-221.
ANDERSON, JR. JOHN D. 1991 Fundamentals of Aerodynamics. (second edition) McGraw-Hill, Inc. p.382-390
CHANG, C. C. ＆ WANG, C. T. 1999 Numerical study of flow about a finite body by a three-dimensional hybrid vortex method. Submitted to Journal of Fluid Mechanics.
CHANG, C. C. 1992 Potential flow and forces for incompressible viscous flow. Proc. Roy. Soc. Lond. 437, 517-525.
CHANG, E. J. & MAXEY, M. R. 1995 Unsteady flow about a sphere at low to moderate Reynolds numbers. Part 2. Accelerated motion. J. Fluid Mech., vol. 303, pp. 133-153.
CHENG, M. T. & CHU, C. C. & LIAO, Y. Y. 1995 Influence of Rotation on the Flow Around and Impulsively Started Circular Cylinder, Bulletin of the College of Engineering, National Taiwan University, 63, 102-115.
CHU, C. C. & CHANG, C. C. & Liu C. C. & CHANG, R. L. 1996 Suction effect on an impulsively started circular cylinder: Vortex structure and drag reduction. Physics of Fluids, 8(11), 2995-3007.
CHU, C. C. & LIAO, Y. Y. 1992 A Quantitative Study of the Flow around an Impulsively Started Circular Cylinder. Experiments in Fluids, 13, 137-146.
CHU, C. C. & WANG, C. T. & CHANG, C. C. & CHANG, R. Y. & CHANG, W. C. 1995 Head-on Collision of Two Coaxial Vortex Rings-Experiment and Computation, Journal of Fluid Mechanics, 296, 39-71.
CHU, C. C. 1987 A Study of Turbulence Production and Modification in boundary Layers Using a New Photochromic Visualization Technique. Ph.D. Dissertation, Michigan State University, Dec. 1987.
COUTANCEAU, M. & BOUARD, R. 1977 Experimental determination of the main features of the viscous flow in the wake of a circular cylinder in uniform translation. Part 1. Steady flow, pp.231-256 AND Part 2. Unsteady flow, pp.257-272, J. Fluid Mech.
COUTANCEAU, M. & BOUARD, R. 1980 The early stage of development of the wake behind an impulsively started cylinder for 40 < Re < 104. J. Fluid Mech., vol. 101, part 3, pp. 583-607.
DENNIS, S. C. R. & WALKER, J. D. A. 1972 Numerical solution for time-dependent flow past an impulsively started sphere. Phys. Fluids 15, 517-525.
FALCO, R. E. & CHU, C. C. 1987 Measurement of Fluid dynamic quantities Using A photochromic Grid Tracing Technique. Presented in SPIE 31st Annual Meeting.
GOLDBURG, A. & FLORSHEIM, B. H. 1966 Transition and Strouhal number for the incompressible wake of various bodies. Phys. Fluids 9, 45-50.
KALRO, V. & TEZDUYAR, T. 1998 3D computation of unsteady flow past a sphere with a parallel finite element method. Comput. Methods Appl. Mech. Engrg. 151, 267-276.
KIM, I. & PEARLSTEIN, A. J. 1990 Stability of the flow past a sphere. J. Fluid Mech. vol. 211, pp. 73-93.
MőLLER, W. 1938 Experimentelle Untersuchengen zur Hydrodynamik der Kugel. Phys. Z. 39, 57-80.
MONKEWITZ, P. A. 1988 A note on vortex shedding from axisymmetric bluff bodies. J. Fluid Mech. vol. 192, pp. 561-575.
NAKAMURA, I. 1976 Steady wake behind a sphere. Phys. Fluids vol.19, 5-8.
NEVE, R. S. & SHANSONGA, T. 1989 The effects of turbulence characteristics on sphere drag. Int. J. Heat and Fluid Flow, Vol. 10, No. 4, 318-321.
RIMON, Y. & CHENG, S. I. 1969 Numerical solution of a uniform flow over a sphere at intermediate Reynolds numbers. Phys. Fluids 12, 949-959.
ROOS, F. W. 1968 An experimental investigation of the unsteady flow about spheres and disks. Ph.D. dissertation, University of Michigan.
ROOS, F. W. & WILLMARTH, W. W. 1971 Some experimental results on sphere and disk drag. AIAA J. 9, 285-291.
TANEDA, S. 1956 Studies on wake vortices (III). Experimental investigation of the wake behind a sphere at low Reynolds numbers. J. Phys. Soc. Japan 11, 1104-1108.
TOULCOVA, J. & PODZIMEK, J. 1968 Contribution to the question of the catching of aerosol particles in the wake of falling water droplets. J. Rech. Atmos. 3, 89-95.
TRITTON, D. J. 1988 Physical Fluid Dynamics.(Second Edition) Oxford University Press 1988, p.109-112.
ZIKMUNDOVA, J. 1970 Experimental investigation of the wake behind a sphere and a spheroid for Reynolds numbers from 44 to 495. J. Rech. Atmos. 4, 7-18.