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研究生:陳昭銘
研究生(外文):Chen, ChaoMing
論文名稱:表面粗糙物對穿音速邊界層轉換之影響
論文名稱(外文):The effect of surface roughness on transonic boundary layer transition
指導教授:苗君易苗君易引用關係
指導教授(外文):Miau, JiunJih
學位類別:碩士
校院名稱:國立成功大學
系所名稱:航空太空工程學系
學門:工程學門
學類:機械工程學類
論文種類:學術論文
論文出版年:1998
畢業學年度:86
語文別:中文
論文頁數:55
中文關鍵詞:邊界層轉換視流觀察壓力擾動
外文關鍵詞:boundary layer transitionflow visualizationpressure fluctuatiion
相關次數:
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本研究以成功大學航太科技中心之穿音速風洞,進行二維平板模型
的風洞實驗,並添 加粗糙物平板表面。在實驗中觀察不同的粗糙物大小
及置放位置對邊界層層紊流轉換現象 的影響,並嘗試以視流觀察及表面
壓力擾動量測的方法來決定邊界層轉換的位置。 為了使平板之邊界層層
紊流轉換區位於平板適當位置以便量測,平板前緣採用自然層流機 翼前
緣。實驗之馬赫數分別為0.338,0.645及0.835,對應的雷諾數分別為
3.73E6,6.34 E6 ,及7.33E6 ,平板與入流角度α分別為0度,-5度
與-10度,其壓力量測與視流觀察的 結果顯示當測試馬赫數相同的條件
下,α角負值增大時,機翼前緣設計所造成的前緣氣流 加速效果減弱,
且層紊流邊界層轉換區會往下遊移動;在α角相同的條件下,測試馬赫數
增加時,機翼前緣設計所造成的前緣氣流加速效果增強,層紊流邊界層轉
換區會變小,並 且會往上游移動。 在平板表面適當為位置加上粗糙物
後,會提前層紊流邊界層轉換的發生。而將風洞的透孔 壁以膠布封住時
,可以降低大部份的風洞噪音來源,減少量測的壓力擾動量。
The purpose of this study is to investigate the effect
of the size and location of surface roughness on the boundary
layer transition in transonic regime. The results obtained
include the surface pressure fluctuation measurements and
surface flow visualizations. The experiments were conducted in
a 600mm×600mm transonic wind tunnel located at the Aerospace
Science and Technology Research Center of National Cheng-Kung
University(ASTRC/NCKU). The leading edge was designed
for the purpose of having natural laminar flow developed
downstream. The test Mach numbers studied are 0.338, 0.645 and
0.835, and the corresponding Reynolds number are 0.338, 0.645
and 0.835, respectively. For the flat plate case without
surface roughness element, the plate is inclined 0°, -5 °,
and -10 ° with respect to the incoming flow. The results of
the pressure fluctuation measure surface flow visualization
that show at a fixed Mach number the laminar-turbulent boundary
transition region would move downstream, and the leading edge
effect gets weaker as the negative incoming flow angle gets
larger. As Mach number increases, for the same incoming flow
angle the transition length gets shorter and the transition
point moves upstream and the leading edge effect gets stronger.
The end points of the boundary transition would move upstream
when the plate was roughened. Sealing the holes on the test
section walls with tapes would reduce the pressure
fluctuations measured on the plate surface substantially,
signifying that the pressure fluctuations in the tunnel induced
by the edgetone effect on the walls is not negligible.
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