本論文主要在利用風洞實驗探討有限翼展在低雷諾數下的氣動力過度現象與其尾流特性。在氣動力參數量測方面，利用六分量力平衡儀去量得升力以及阻力係數。實驗結果顯示，機翼在過渡現象發生的前後會有很不同的氣動力特徵，在接近失速攻角會有遲滯現象。而過渡現象會隨著雷諾數及攻角而變化；當雷諾數越高時，流場過渡所需的攻角越低。
在流場量測方面，使用熱線測速儀量測機翼中心近尾流區的速度場分布可以進一步佐證其流場現象，受到上游機翼表面層流分離不回貼到層流分離泡產生所主導。並利用頻譜分析得到其尾流的特徵頻率。在過渡現象發生前，大尺度的尾流主導整個流場並出現一個明顯的特徵頻率；在機翼表面流場過渡並產生分離泡後，尾流尺度縮小，主頻頻寬變大。在遲滯現象發生之時同一個攻角存在兩種不同的流場，其無因次頻率分別為0.80與0.18。

This thesis experimentally studies the aerodynamic transition and corresponding flow field in the near wake region of a finite wing at low Reynolds numbers. The aerodynamic properties were measured including lift and drag coefficients by a six-component force/moment balance. The results indicate aerodynamic characteristics change after transition and hysteresis phenomenon happens near the stall angle of attack. Nevertheless, transition phenomenon varies with the operating Reynolds number and angle of attack.
In addition, hot-wire anemometers were also applied to measure the near-wake velocity profiles at the vertical mid-span. The mean velocity profiles in the near wake region indicate the upstream surface flow is separated or reattached at low angle of attack and different Reynolds number. Spectral analysis was employed to uncover the coherent structure in wake. A dominant peak was observed before transition; in contract, it broadens with the formation of laminar separation bubble. Two different flow fields were measured under hysteresis loop at the same angle of attack and their Strouhal numbers are 0.80 and 0.18 respectively.

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