臺灣博碩士論文加值系統

開縫圓柱繞流作為鈍體繞流研究的分支，具備很強的應用前景。本研究使用結構性頻譜元素法來進行數值模擬，探究縫隙對開縫圓柱流場結構的影響，在本研究中為Re = 100,200的模擬流場，在縫寬比(S/D)=0.08~0.20的研究中能發現在縫隙口處會有週期性抽吸的現象並且和尾流結構有相位差。
在縫寬比(S/D)=0.10縫隙傾斜角deg = 0°~75°的實驗研究中表明，在一定的雷諾數內，開縫圓柱縫隙的存在從根本上改變了圓柱繞流近區尾流的結構，其圓柱脫落渦的脫落頻率對開縫圓柱縫隙傾斜角具有一定的敏感性，並且隨著縫隙傾斜角的增大其史托克數逐漸變大。

Vortex shedding from a circular cylinder with a slit which belongs to the unsteady flow of bluff bodies has very strong application prospects. In this research, conforming spectral element method is used to simulate flow past slit cylinder. In this study, simulations were conduct with Re=100、200, the slit ratio (S/D) ranges from 0.08 to 0.2. For slit ratios studied, the periodic blowing/suction at the slit opening, and had a phase difference from the wake structure.
In this study, the deg ranges from 0° to 75° of the slit ratio 0.1. The experimental results show that the flow in the slit demonstrates periodic motion, and this oscillating vent-flow greatly alters the near wake flow features within a certain range of Reynolds number. Shedding vortex frequency of slit cylinder has certain sensitivity with the angle of slit. The Strouhal number increases gradually with the increase of the angle.

摘要 i
ABSTRACT ii
目錄 iii
圖目錄 v
第一章 緒論 1
2.1 研究背景與動機 1
2.2 文獻回顧 2
2.2.1 頻譜元素法 2
2.2.2 單一圓柱、縫隙圓柱 3
第二章 數值分析方法 9
3.1 頻譜元素法 9
3.2 流場參數 11
3.3 數學模型 12
3.4 邊界條件設定 13
3.5 網格獨立性 15
3.6 數值模擬驗證 16
第三章 開縫圓柱模擬分析 18
4.1 縫隙圓柱模擬規劃 18
4.2 Re100α= 90° 模擬結果與分析 19
4.2.1 S/D = 0.1α= 90° 流場現象 19
4.2.2 S/D = 0.1α= 90° 渦流現象 23
4.2.3 通過縫隙的體積流量(CQ) 25
4.2.4 縫寬效應 27
4.2.5 史托克數(Strouhal Number, St)分析 37
4.2.6 Re100 傾角α°=90 結論 40
4.3 Re100 S/D = 0.1開縫圓柱 傾角deg 模擬結果與分析 41
4.3.1 傾角deg流動型態 41
4.3.2 S/D = 0.1 deg = 0° ~ 75° 渦流現象 49
4.3.3 通過縫隙的體積流量(CQ) 51
4.3.4 角度效應 52
4.3.5 史托克數(Strouhal Number, St)分析 63
4.3.6 Re100 S/D = 0.1開縫圓柱 傾角α° 結論 66
第四章 總結論與未來展望 67
5.1 總結論 67
5.2 未來展望 67
參考文獻 68

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