Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/1933
標題: 匿蹤飛行器模型之靜態與動態高攻角氣動力特性研究
Experimental Investigation on Aerodynamic Characteristics of Statics and Dynamics of Stealth Aircraft Model at High Angle of Attack
作者: 邱冠儒
Cho, Guan-Zu.
關鍵字: stealth;Array匿蹤 仰俯速率 渦漩崩散 搖滾現象;pitch rate;burst vortex;wing rock
出版社: 機械工程學系
摘要: 
本文主要內容有說明其匿蹤外型之設計方法資料以及使用水洞流場來觀測並探討具匿蹤之飛行器模型(UCAV)在靜態與動態條件下其高攻角流場特性。實驗參數為側滑角,攻角及動態俯仰速率(Pitch Rate)、在上仰(Pitch Up)及下俯(Pitch Down)等條件下,觀察其渦漩崩散(Burst Vortex)的位置。實驗結果發現,模型為W型的尾翼其所造成之渦漩使得機身上的渦漩更為混亂,除了造成崩散點提前發生之外,更因尾翼渦漩的回流效應使前機身渦漩分裂成雙渦漩。在靜態條件下,當具匿蹤外型飛行器之攻角增加,其渦漩崩散點會往翼前緣移動,且其左右兩側產生之渦漩崩散位置基本上是對稱的。而在動態條件下,具匿蹤外型飛行器產生之渦漩崩散位置會有延遲現像;且在零側滑角之情況下,其左右兩側之渦漩崩散位置會形成不對稱之崩散情況,此現象可能造成飛機產生不穩定之滾轉(Wing Rock)情形。當具匿蹤外型飛行器攻角上仰過程中,渦漩崩散位置比攻角下俯過程中較為延遲,且隨著俯仰速率的增大,其所造成渦漩崩散位置的延遲發生則更為明顯。
測力研究方面,探討模型在靜態與動態條件下的氣動力特性,利用五分量平衡儀(N1,N2,S1,S2,RM)量測其CN、Cl和Cm值。實驗結果發現,正向力係數與攻角的曲線中,遲滯環的出現是由於翼面上的不同流態對外界擾動的反應時間不同所造成的,俯仰速率越快,遲滯環狀量越大。模型上仰過程中俯仰速率的增加,可進一步提高最大正向力係數,延遲失速攻角;模型下俯過程中俯仰速率的增加,會降低遲滯環內之最小正向力係數。

The aerodynamics and stealth often conflict each other in designing the stealth aircraft shape. In this research, we study the static and dynamic behaviors at high angle of attack of UCAV by water tunnel experiment. In order to investigate the burst vortex position, we use parameters including pitch angles, sideslipe angles, action pitch rate in pitch up and pitch down process. The experiment results show that model W type empennage has irregular vortex not only for the model. It also leads to an early burst position and other tail vortex to form backflow effect. This effect will lead to a split form of airframe vortex. In static state, burst vortex points move toward the front side of wing when the angle of attack of UCAV increases. In the dynamic state of UCAV model, the right and left burst vortex position are both delayed with unstable rocking at zero sideslip angle.
Investigation results show that while increase the pitch-up rate, the maximum lift-up coefficient and stall angle of attack will increase. During the process of pitch down, the reduction of pitch rate will decrease lift-up coefficients and stall angle. Different pitch rates affect other aerodynamic coefficient, and the control of plane simultaneously.
URI: http://hdl.handle.net/11455/1933
Appears in Collections:機械工程學系所

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