本論文主要利用風洞實驗以探討低雷諾數下對機翼表面粗糙度及氣動力過渡現象之影響及特性。在氣動力參數量測方面，機翼的升力、阻力可利用六力平衡儀量得，為了輔證所得到的資料，也利用煙線視流實驗去觀察翼表面的流場變化。根據實驗結果顯示，在雷諾數方面，隨雷諾數的增加(5×104~1.3x105)，粗糙表面之機翼遲滯現象並非線性變化，且於雷諾數較低時，攻角遲滯現象的大小會先隨著雷諾數的增加而變大，之後隨即再度縮小，反映出攻角遲滯現象在低雷諾數效應下，產生及消失之機制乃因機翼上表面流場之分離及回貼特性受表面粗糙度及雷諾數之改變而影響。另外、根據煙線視流實驗探討，藉由分離泡發生時之層流分離點及回貼點對比，發現粗糙表面比光滑表面有較佳之分離泡形成及結構特性。另外藉由機翼表面粗糙度的改變，在相同的雷諾數模態下會有很不同的氣動力特徵，於過渡區間之雷諾數範疇界於5x10 <Re<1.3x10 中，研究升/阻力的變化、翼上緣分離泡的形成分佈及造成之遲滯現象的表現，發現光滑翼面升力較高，然攻角遲滯現象之發生乃隨粗糙度之增加而減少，這也跟力量測實驗結果相互輝映。另外觀察經處理過之粗糙表面升力雖較光滑翼面低，但因遲滯圈的收斂顯得氣動力表現較穩定，這對小型飛行器於低雷諾數環境下飛行較有益。

In order to realize the influencesd of aerodynamic characteristics and transition phenomenon on the roughness surface of wings, this thesis experimentally studies the aerodynamic performance and corresponding flow structures on the upper surface of wing at the critical Reynolds numbers between 104~105. The aerodynamic properties include the lift drag coefficients with three different roughness effects for aspect ratios equal to 6.0, and further study is made on the flow visualization along the span-wise direction of flow structures on the upper surface of wing. According to the experimental results, the nonlinear hysteresis loop regarding the lift coefficient curve with angle of attack is observed following the variation of Reynolds numbers, and the ranges of Reynolds numbers in which the hysteresis phenomenon was clearly observed in lift and drag coefficients are lied between 5×104 and 1.3×105.And the hysteresis phenomenon was also clearly noted with the decrease of roughness effects on the upper surface of wing. For the experiment of smoke wire visualization on the middle line of the wing at upper surface with span-wise flow direction, the range of separation and reattachment point and separation bubble are clearly shown to follow the increase of the angle of attack without stall. All of the experimental results in the present study can also provide a data base for the simulation of aerodynamic and fluid dynamic researches.

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