本論文以實驗方法研究三維薄板低展弦比(AR=1.0~2.0)機翼在雷諾數介於5x104~1x105條件下之空氣動力特性及流場結構，主要在探討展弦比的影響。實驗所量測的基本空氣動力特性包含升力、阻力及俯仰力矩係數，並進一步分析與討論升力係數之線性與非線性特徵、升阻比、低雷諾數效應及誘導阻力特性。三維流場結構之觀察實驗於低速煙洞中進行，主要觀察低展弦比機翼翼尖渦流結構，並配合實驗結果進行分析比較。根據實驗分析及流場觀察結果得知，翼尖渦流與機翼上翼面流場之交互作用對低展弦比機翼之空氣動力特性有極大的影響，使得低展弦比薄翼擁有較高的失速攻角，並且具有非線性升力變化特性。這兩種特性均與展弦比有關。當展弦比低於1.3時，失速攻角即大幅增高；而展弦比低於1.6時，低攻角範圍(00~150)的非線性升力特性即十分顯著。由此結果可知，在高攻角與低攻角範圍下，翼尖渦流影響翼表面氣流的型態並不相同。在本實驗的雷諾數範圍內，空氣動力特性並未隨雷諾數變化而有明顯改變，升力及阻力與攻角之關係也無遲滯現象存在。本論文各項結果，可作為低展弦比微飛行器設計所需之參考。

　　The thesis experimentally studies the aerodynamic performances and the corresponding flow structures on thin-plate wings with aspect ratios between 1.0 and 2.0 and Reynolds numbers between 5x104~1x105 in a low speed wing tunnel. The measurements of the wing models include lift, drag and pitch moment, and the aerodynamic properties to be analyzed contain the slopes of linear and nonlinear lift curves, lift to drag ratios, low Reynolds numbers effect and induce drag. The investigation of flow structures was conducted by smoke-wire visualization technique to realize the flow behaviors in a smoke tunnel. According to the results of experiments, the aerodynamic properties for low aspect ratio thin-plate wing below 1.3 was deeply affected by the generation of tip vortices on the upper surface of wing models which causes the higher stall angle of attack appear to be nonlinear for the aspect ratios below 1.6 within the angle of attack ranges between 00and 150. The effect of low Reynolds numbers on lift and drag coefficients in low aspect ratio wings confirms that the hysteresis phenomenon was not apparent in the present study. In steady, regarding the lift-to-drag ratios, the increase of lift force would follow the increase of drag force which clearly causes the maximum lift-to-drag ratio to occur at the low angle of attack between 30 to 60 .All of the experimental results in the present thesis can provide a data base for the design of micro aerial vehicle using the thin-plate for wings.

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