自1976年Richard T. Whitcomb指出加裝翼尖小翼(Winglet)飛機其空氣動力性能較一般翼尖裝置更能明顯提高後,翼尖小翼便成為改善飛機空氣動力性能的主要方法。本文以計算流體力學方式,利用現有軟體進行螺旋狀翼尖小翼之模擬,探討其應用於一般商務客機時其空氣動力性能之變化;同時亦嘗試施加噴流在翼尖附近,以期進一步提升飛機之總體性能。吾人採用之機翼乃Gulfstream Ⅳ此一小型客機的主翼參數,而其翼剖面則是採用Whitcomb所設計的超臨界翼剖面(Supercritical Airfoil),以比較未安裝、安裝螺旋狀翼尖小翼和安裝且施加噴流三種情況的升力係數、阻力係數和升阻比;其中螺旋狀翼尖小翼又依其環狀小翼的位置分為前旋與後旋兩種情況。最終目的是找出減阻最多並且有效潰散渦流強度的最佳化結果,不僅提升飛行效率,也能改善飛行安全。 Since 1976 Richard T. Whitcomb has shown that the efficiency of the aircraft equipped with winglet is better than other devices set at the wingtip, winglets are now incorporated into most new commercial and military transport jets. In this paper, the geometry of the wing is of Gulfstream IV, and its airfoil is chosen of Whitcomb's supercritical airfoil. The three different configurations are the bare wing of no wingtip device, the wingtip equipped with spiroid winglet, and blowing on the spiroid winglet. The goal of blowing at the wingtip is to advance the customary time of decaying trailing vortices and to reduce the strength of trailing vortices. Consider the spiroid winglet and blowing at wingtip coupled together, and we could find an optimal result that reduced the total drag as well as the strength of the trailing vortex, thus the flight could become most efficient.