本研究主要探討低展弦比平板機翼的翼尖渦流隨攻角變化之發展情形。實驗是以展弦比1之平板機翼作為量測模型，實驗過程中風洞的風速維持在13m/s，也就是雷諾數為Re=8×10^4，模型攻角範圍為10～50度，以X型熱線測速儀在機翼後方量測以得到流線方向及機翼方向的瞬時速度與擾動量，經由資料分析後，可以看到翼尖渦流之結構隨攻角變化而變動之情形，並藉由流場等高線分佈圖可以明顯看出翼尖渦流對低展弦比平板機翼中心流場在不同攻角下的影響。
本研究探討了展弦比變化對翼面中心流場之影響，實驗結果證實，AR＝1與AR＝2、3的翼面中心流場明顯不同，AR＝2、3翼面中心失速角度約在20之前，而AR＝1機翼翼面中心失速角度提高至40度之後，AR＝1翼面中心流場速度在25度之後被加速，加速情形在33度之後消失，相同情形在AR＝2與AR＝3時並未發現。
在本研究中亦發現，翼尖渦流之大小及其渦流中心位置和翼後緣之垂直距離隨著攻角增加而增加，而翼尖渦流在翼面上嚴重影響的區域在攻角35度前隨著攻角增加而增大，並在攻角35度後隨著攻角增加而減小。根據實驗結果可將流場的變化情形區分成兩類，在第一類中(攻角小於35°)，翼尖渦流中心停留在翼面之上，翼尖渦流之垂直分量抑制翼面中心流場分離程度；而在第二類中((攻角大於35°))，翼尖渦流中心開始向翼面外移動，翼尖渦流對翼面中心流場影響明顯減緩。

This thesis studies the flow structures of wing tip vortex on thin-plate wing at different angles of attack. The thin-plate wing model with AR = 1 was operated at free-stream velocity of 13m/s, corresponding to chord-based Reynolds number of 8×10^4. The wing model was tested at the angles of attack ranging from 10° to 50° in these experiments. The flow properties were obtained by streamwise and spanwise mean and fluctuation velocities measured by a cross-type hot wire anemometer.
Experimental results show that the velocity profile of the wing of AR = 1 is very different with that of AR = 2 and 3. At AR = 1 the stall angle is after AOA = 40°, but the stall angle of AR = 2 and AR = 3 is about AOA = 20°, these result are in good agreement with previously published researches.
More detail flow properties of AR = 1 was investigated. Experimental results indicate that the vortex size and the distance between vortex core and trailing edge increases as angle of attack increases. The area of highly affected region increases as angles of attack increases, reaches the maximum at AOA = 35°, and decreases as angles of attack increases furthermore. From the contours of streamwise and spanwise mean velocities, the flow field can be divided into two types. In the first type where the AOA is less than 35°, the vortex core stands at the upper surface of the wing, the vertical component of tip vortex accelerates partially flow field on the upper surface to suppress the flow separation on the upper surface, in this type the affection of tip vortex is getting stronger when angles of attack increases. While in the second type where the AOA is larger than 35°, the vortex core starts to shift away from the root of the wing, and the vortex size continues to grow up with deformed flow structures.

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