本論文主要利用風洞實驗以探討有限機翼在低展弦比以及低雷諾數下的氣動力特性。在氣動力參數量測方面，機翼的升力、阻止以及俯仰力距可利用三力平衡儀量得，為了輔證所得到的資料，也利用表面油流實驗去觀察翼表面的流場變化，除此之外，為了提升本機翼在高攻角時的氣動力特性，在翼前緣附近也安置了利用微機電技術所製造的微泡致動器。實驗結果顯示，在低雷諾數下的流場會存在有三種雷諾數模態，它們分別是次臨界、臨界、以及超臨界雷諾數模態，在不同的雷諾數模態下會有很不同的氣動力特徵，而這模態會隨雷諾數以及攻角而變化；當雷諾數愈高時，由次臨界雷諾數轉換至臨界雷諾數所需的攻角愈低，而不同模態下的流場情形也可經由油流實驗中觀察得知。除此之外，在表面油流實驗中，也可以發現在翼尖端的分離泡很明顯受到翼尖渦流的影響，此時在翼尖端的分離泡會比翼中央來的小。從展弦比為1的氣動力參數分析，可以發現此時的流場特性很明顯的受到翼尖渦流的影響，即三維效應變的很明顯，雖然翼尖渦流可能促進雷諾數模態的提早發生，但是整體的氣動力性能會相對的降低很多。對於次臨界雷諾數範圍下，微泡致動器可以有效提升微飛機的氣動力特性，且激擾位置在靠近層流分離點附近其效果最大。但隨著雷諾數的持續增加，其效益會逐漸降低，甚至產生反效果。

This thesis is intended to study experimentally the aerodynamic performance of the finite wing at low aspect ratios and in low Reynolds numbers by means of the wind tunnel testing. The 3-component force/moment balance and surface oil-flow technique are respectively used to study the aerodynamic performance and flow field characteristics about the wing. The bubble actuator made of Micro-electrical-mechanical system (MEMS) technique is employed and installed around the leading edge to enhance the aerodynamic performance in high angles of attack of the wing. Results indicate that three different Reynolds number modes of aerodynamic performance are found as functions of the Reynolds number and the angle of attack both in the operating ranges. That is, the subcritical, critical, supercritical behaviors of the aerodynamic performance can be characterized in terms of the Reynolds number and angle of attack as well. For the lower aspect ratio of the wing tested, the 3-dimensional, tip-vortex effect will be more significant in influencing the aerodynamic performance, which is also witnessed by the oil-flow visualization. Within the subcritical Reynolds number range, the bubble actuator can effectively improve the aerodynamic performance of the wing, especially when the actuator is situated close to the separation point of the boundary layer over the upper wing surface. However, it is less effective on the aerodynamic performance when the operating Reynolds number is greater than the critical value. The efficiency of the bubble actuator excitation gets even unfavorable when the Reynolds number increases to some extent beyond the critical one.

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