Back to Search Start Over

Transition mechanism, prediction, and control of crossflow field

Authors :
Kohama, Yasuaki
Egami, Yasuhiro
Kawakami, Mitsuyoshi
Haruta, Yoshiyuki
Shimagaki, Mitsuru
Source :
航空宇宙技術研究所特別資料: 第28回境界層遷移の解明と制御研究会講演論文集 = Special Publication of National Aerospace Laboratory: Proceedings of the 28th NAL Workshops on Investigation and Control of Boundary-Layer Transition. 54:31-34
Publication Year :
2002
Publisher :
航空宇宙技術研究所, 2002.

Abstract

Through systematic investigation concerning the crossflow dominant boundary layer transition, the complicated transition mechanism was clarified experimentally. Namely, transition starts with stationary streamwise vortex (crossflow vortex) generation. This is called 'primary instability'. Then, primary instability induces three unsteady instabilities, F(sub 1), F'(sub 1)(relatively low frequency), F(sub 2) (relatively high frequency). F(sub 1) travels to crossflow direction, F(sub 2) travels to streamwise direction, and F'(sub 1) travels to the opposite direction with F(sub 1). It seems to be that F(sub 2) enhances the transition into full turbulent. Taking into consideration of such flow mechanism, a prediction method has been developed by introducing C(sub 1), C(sub 2) which is valid in general three-dimensional boundary layer transition. Knowing the threshold value for critical condition either by experimentally, or numerically, it is possible to predict transition onset simply calculating potential flow information. A unique and practical selective suction method to delay the transition with less suction power. It was possible to delay the transition with one third of the power of uniform suction.<br />資料番号: AA0032827009<br />レポート番号: NAL SP-54

Details

Language :
Japanese
ISSN :
0289260X
Volume :
54
Database :
OpenAIRE
Journal :
航空宇宙技術研究所特別資料: 第28回境界層遷移の解明と制御研究会講演論文集 = Special Publication of National Aerospace Laboratory: Proceedings of the 28th NAL Workshops on Investigation and Control of Boundary-Layer Transition
Accession number :
edsair.jairo.........b56989fe18e6d5cec64b25a2ee43106e