臺灣博碩士論文加值系統

本研究之目的旨在針對不同高寬比(aspect ratio, H/W)對直立式平板前緣穩定運動狀態馬蹄形渦流系統特性所造成之影響，進行深入分析探討。運用精密之PIV量測系統，可對於流場中長時間與瞬時全域流場之量測，使得原本未知的直立式平板前緣穩定運動狀態馬蹄形渦流流場特性能夠更加明瞭。
本文針對Re = 200 ~ 1200範圍內，深入探討H、W與δ三原始參數對於流場特性之影響，變化不同高寬比(H/W = 1 ~ 4)與δ(H/δ = 0.5 ~ 9, W/δ = 0.5 ~ 3)條件，分析馬蹄形渦流結構的特性變化，得到H/W、H/δ與W/δ三無因次參數對主渦渦心之水平與垂直位置、平板前緣中心軸面之下降流強度及停滯點的相關性。並對於流場結構以拓樸學理論進行渦流結構分析與其速度剖面探討。

ABSTRACT
The laminar boundary layer on the wall ahead of a vertical plate is in a region of adverse pressure gradient, and within some distance upstream of the body this boundary layer experiences a three-dimensional separation. In the separated region, a system of vortices is developed and stretched around the base of the body like a horseshoe shape. The characteristics of steady horseshoe vortex system near the juncture of a vertical plate and a horizontal bottom was studied experimentally using particle image velocimetry (PIV). The purpose of the present study is to provide Several detailed flow structures in the steady type, regarding the position of primary vortex core, down-flow velocity, and the position of stagnation point on the model are discussed. The range of aspect ratio (H/W) is from 1 to 4 for the Reynolds number Re, based upon the free stream velocity (U0 ) and the width of vertical plate (W), is form 200 to 1200.

目 錄
誌 謝 Ⅰ
中文摘要 Ⅱ
英文摘要 Ⅲ
表 目 錄 Ⅵ
圖 目 錄 Ⅷ
相片目錄 ⅩⅢ
符號說明 ⅩⅤ
第一章 緒論
1-1 研究動機 1
1-2 相關文獻回顧 3
1-3 本文組織 10
第二章 實驗設備佈置及分析方法
2-1 實驗水槽及模型佈置 13
2-1-1 循環水槽 13
2-1-2 拖曳式平台 13
2-1-3 實驗模型 15
2-1-4 實驗佈置 15
2-1-5 實驗條件分佈. 18
2-2 流場可視化實驗佈置及方法 21
2-2-1 可視化實驗佈置 21
2-2-2 可視化實驗之追蹤物質(tracer) 23
2-3 FLDV量測系統及實驗佈置 23
2-3-1 二維FLDV系統 23
2-3-2 二維FLDV系統之佈置 26
2-3-3 實驗資料分析方法 26
2-4 PIV量測系統及實驗裝置 28
2-4-1 PIV量測系統 28
2-4-2 PIV之運作與計算原理 32
2-4-3 PIV量測系統之佈置 34
2-5 渦度分析與環流量計算 34
第三章ˉ初步實驗
3-1 平板邊界層平均速度剖面量測 37
3-2 流場壓力梯度檢測 37
3-3 邊界層發展檢測 39
3-4 平板流場Z方向二維性檢測 39
3-5 圓柱實驗印證 41
3-6 PIV量測實驗檢測 43
3-7 PIV系統於低流速下運作之檢測 45
3-8 玻璃與壓克力平板之相同性檢測 47
3-9 馬蹄型渦流流場之再現性檢測 52
第四章ˉ平板前緣穩定運動狀態馬蹄型渦流系統特性
之分析探討
4-1 各類穩定運動渦流系統之流場結構拓撲理論與速度剖面分析 55
4-1-1 二渦渦流結構系統 56
4-1-2 四渦渦流結構系統 56
4-1-3 六渦渦流結構系統 60
4-1-4 八渦渦流結構系統 ….60
4-2 主渦渦心位置變化分析探討……………………………65
4-2-1 主渦渦心之垂直位置變化分析探討 65
4-2-2 主渦渦心之垂直位置變化分析探討 82
4-3 直立式平板前緣中心軸面之下降流強度分析 85
4-4 停滯點之位置變化分析 88
第五章ˉ結論與建議
5-1 結論 90
5-2 建議 92
參考文獻 93
附 錄 96

1. Schwind, R.：The Three- Dimensional Boundary Layer Near a Strut, Gas Turbine Lab. Rep., MIT, 1962.
2. Hunt, J. C. R., Abell, C. J., Peterka, J. A., and Woo, H. J. ：Kinematical Studies of the Flows around Free or Surface-Mounted Obstacles; Applying Topology to Flow Visualization, Journal of Fluid Mechanics, Vol. 86, Part 1, pp. 179-200, 1978.
3. Baker, C. J.：The Laminar Horseshoe Vortex, Journal of Fluid Mech., Vol. 95, Part 2, pp. 347-367, 1979.
4. 岡本史紀：平面上正方形斷面鈍物體過流實驗的研究, 日本機械學會論文集，第50卷， pp. 2068-2076，1983。
5. Kimura, I., Takamori, T.：Image Processing of Flow around a Circular Cylinder by Using Correlation Technique, Flow Visualization IV (ed. Veret, C.), pp. 221-226, 1986.
6. Thomas, S. W.：The Unsteady Characteristics of Laminar Juncture Flow, Physics of Fluid, pp. 283-285, 1987.
7. Greco, J. J.：The Flow Structure in the Vicinity of a Cylinder- Flat Plate Junction: Flow Regimes, Preiodicity, and Vortex Interactions, MS Thesis, Department of Mechanical Engineering and Mechanics, Lehigh University, 1990.
8. Su, T. C. and Lian, Q. X.：The Tip-Ward Flow over a Surface Mounted Bluff Body, FIV, pp. 39-44, 1990.
9. Baker, C. J.：The Oscillation of Horseshoe Vortex System, Journal of Fluids Engineering, Vol. 113, pp. 489-495, 1991.
10. 蔡銹樺：鈍形體馬蹄型渦流行為之探討，國立成功大學工程科學研究所碩士論文，1993。
11. Taketoshi Okuno and Shigeru Nishino：Observation of Horseshoe Vortex in Juncture Flow, Third Asian Symposium on Visualization, pp. 128-133, 1994.
12. Seal, C. V., Smith, C. R., and Rockell, D.：Quantitative Characteristics of a Laminar, Unsteady Necklace Vortex System at a Rectangular Block-Flat Plate Juncture, Journal of Fluid Mech., Vol. 286, pp. 117-135, 1995.
13. 葉建忠：柱體周邊三維流場之觀測與量測，國立中興大學土木工程研究所碩士論文，1996。
14. Seal, C. V., Smith, C. R., and Rockell, D.：Dynamics of Vorticity Distribution in Endwall Junctions, AIAA Journal, Vol. 35, No. 6, pp. 1041-1047, 1997.
15. Bruce Melville：Local Sour at Piers and Abutments, Short Course Lecture Notes-Workshop on Bridge Scouring, Lecture 4, 1998.
16. Rockwell, D.：Vortex-Body Interactions, Annual Reviews of Fluid Mech., pp. 199-229, 1998.
17. 陳謹偉：應用PIV及FLDV於矩形柱體來流端馬蹄型渦流流場之探討，國立中興大學土木工程研究所碩士論文，1999。
18. 邱鵬豪：應用PIV及FLDV於直立式平板前緣馬蹄型渦流特性之分析研究，國立中興大學土木工程研究所碩士論文，1999。