JAXA Repository / AIREX 未来へ続く、宙(そら)への英知
49194000.pdf8.78 MB
Other TitleInfluence of the external disturbances on natural transition in boundary layers on NACA0012 airfoil
Author(jpn)徳川 直子; 高木 正平; 上田 良稲; 井門 敦志
Author(eng)Tokugawa, Naoko; Takagi, Shohei; Ueda, Yoshine; Ido, Atsushi
Author Affiliation(jpn)宇宙航空研究開発機構 総合技術研究本部; 宇宙航空研究開発機構 総合技術研究本部; 東京ビジネスサービス; 鉄道総合技術研究所
Author Affiliation(eng)Japan Aerospace Exploration Agency Institute of Aerospace Technology; Japan Aerospace Exploration Agency Institute of Aerospace Technology; Tokyo Business Service Co. Ltd.; Railway Technical Research Institute
Issue Date2006-02-23
PublisherJapan Aerospace Exploration Agency (JAXA)
Publication date2006-02-23
AbstractA series of experimental investigations have been carried out to examine the influence of free-stream turbulence and acoustic noise on laminar-to-turbulent transition in boundary layers on an NACA0012 airfoil. The quantitative evaluation of the influence on the total growth rate N of the most amplified disturbance obtained from the e(sup N) method at the transition location is made in an empirical relation between the total growth rate N and both the residual turbulence Tu and the sound pressure level SPL. Consequently, the transition location is detected as a linear equation N = C(sub Tu) x ln(Tu) + C(sub SPL) x SPL + C for not only 2-D case with zero angles of both sweep and attack but also 3-D case with non-zero angles of both sweep and attack, though each coefficient in N depends on geometrical configuration of airfoil such as cross-sectional shape and swept angle. Accuracy of predicted chord length is expected to be improved 10 percent by use of the obtained empirical relation. Surface temperature measurement technique by use of infrared camera is shown to be efficient and useful for transition detection in low subsonic flow. Usefulness is also shown in visualizing cross-flow stationary vortices growing in 3-D boundary layer.
e(sup N)法を用いた2次元および3次元境界層の乱流遷移位置の予測において外乱の影響を定量的に評価するため、一様流の残留乱れTuおよび騒音レベルSPLと遷移位置における撹乱の空間増幅率Nの相関関係を実験的に調べた。気流特性が異なる3つの風洞で同一の矩形翼NACA0012模型の遷移計測を実施した。その結果、模型を2次元と3次元形態のどちらに設置しても、NはTuの対数とSPLの1次関数で表されるが、外乱に対する感度は翼断面や後退角に依存することがわかった。この相関関係を用いることにより2次元の場合には遷移位置の予測精度が翼弦長の10%程度向上することが期待される。また低亜音速境界層の遷移位置検出手法として、赤外線力メラを用いた表面温度分布計測が有効であり、横流れ定在渦も可視化可能であることを示した。
DescriptionJAXA Research and Development Report
Keywordsboundary layer transition; transition prediction; NACA0012 airfoil; Preston tube; acoustic noise; wind tunnel test; infrared photography; surface temperature; dynamic pressure; turbulence; transition location; total growth rate; 境界層遷移; 遷移予測; NACA0012翼型; プレストン管; 騒音; 風洞試験; 赤外写真法; 表面温度; 動圧; 乱流; 遷移位置; 空間増幅率
Document TypeTechnical Report
JAXA Category研究開発報告
Report NoJAXA-RR-05-017

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.