本研究最主要的目的在於模擬機翼處於動態失速的狀況下，攻角對於升力的影響，並比較了動態失速與靜態失速的不同。在進行分析時，運用兩種不同的觀察法（傳統尤拉法及拉格朗日連結結構），並從這兩者間找出關聯性，進一步的分析出機翼處於動態失速下的流場。除了觀察壓力場、速度場及渦度等這些在傳統尤拉方法觀測到的數據，並加上質點追蹤及Lagrangian Coherent Structures (LCS)。
從模擬結果可以得知在動態失速下，影響升力最主要的因素為渦旋的強度、所處的位置及不同攻角造成下表面的高壓區強度、面積大小有關。上表面的順時針渦旋通常都是會使升力上升，但須考慮到強度及位置是否接近機翼上表面。尾端逆時針渦旋如果強度夠且成長至機翼尾端上表面附近，則它產生的低壓區能使升力上升，但尾端渦旋離機翼尾端太近則會使機翼下表面尾端流體加速，使機翼下表面壓力降低，這會使升力下降。

The phenomenon of dynamic stall for a single pitching foil is simulated and analyzed in this study. The differences between static and dynamic stall are investigated in terms of lift coefficient. In addition to the traditional Eulerian viewpoint, Lagranigan coherent structures are also utilized to gain more insights of the flow physics.
The result of simulation can capture the dynamic flows effectively on qualitative. It is shown that the strength and location of vorticity will affect the lift, and so does the interactions between high and low pressure area, which are dominated by angle of attack. The leading-edge vortex usually will enhance the lift. As for the trailing-edge vortex, it will reduce the lift. On the other hand, the lift will increase if this vortex is closer to the upper surface.

論文審定書 i
誌謝 ii
中文摘要 iii
Abstract iv
目錄 v
圖次 vii
表次 viii
符號說明 ix
第一章 緒論 1
1.1 前言 1
1.2 文獻回顧 1
1.2.1 動態失速 1
1.2.2 拉格朗日連結結構 3
1.3 研究目的 5
第二章 研究方法 6
2.1 模擬擺動翼片之數值方法與流程 6
2.1.1 紊流之模擬方法 6
2.1.2 動網格之使用 11
2.1.3 流場幾何、邊界條件及網格設定 12
2.1.4 實驗與模擬驗證 15
2.2 拉格朗日連結結構研究方法 18
第三章 結果與討論 20
3.1 動態失速分析 20
3.1.1 靜態與動態機翼比較 21
3.1.2 延遲失速分析 23
3.1.3 機翼失速分析 33
3.1.4 失速後流場分析 44
3.2 三次升力震盪的比較及分析 48
第四章 結論與建議 51
參考文獻 53

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