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NAOSITE : Nagasaki University's Academic Output SITE > Faculty of Engineering > Bulletin > Reports of the Faculty of Engineering, Nagasaki University > Volume 25, No. 45 >


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Title: 遷移レイノルズ数における翼まわり流れの可視化
Other Titles: Flow Visualization around the airfoils in the Transition Reynolds Numbers
Authors: 林, 秀千人 / 児玉, 好雄 / 肥喜里, 邦彦
Authors (alternative): Hayashi, Hidechito / Kodama, Yoshio / Hikiri, Kunihiko
Issue Date: Jul-1995
Citation: 長崎大学工学部研究報告 Vol.25(45) p. 95-104, 1995
Abstract: We researched the fluctuating flow characteristics on three types airfoils, NACA0008, NACA0015 and NACA65710 in the transition Reynolds Numbers (Re=5450~120000). The visual technique with the video recorder and the camera was used. It was found that the Karman Vortex shedding (wake vortex) was generated in all Reynolds numbers at small attack angles. The core of the wake vortex was clear at the low Reynolds number (Re=5450), but not clear when the Reynolds number increased (Re=16300~120000), Because the dissipation on the shear flow occured just before rolling up of the wake vortex at high Reynolds number. There were two patterns of rolling up of the wake vortex that one was rolling up from the separated boundary layer of the airfoil and another was rolling up in the wake. At the case of rolling up in the wake, the wake voetex was rolling up near the trailing edge of the airfoil at high Reynolds number, but it was rolling up at far downstream of the airfoil at the low Reynolds number. At the case of rolling up from the separeated boundary layer, the wake vortex was always rolling up just behind the dead air region which was generated between two separated shear layears at the trailing edge. When the attack angle increased, the separation bubble on the suction side was generated near the leadind edge, then the turbulent boundary layer developed to the trailing edge. In this case the wake vortex was not rolling up and the dissipated wake was generated, This phenomenon often occuered when the Reynolds number increased.
URI: http://hdl.handle.net/10069/14943
ISSN: 02860902
Type: Departmental Bulletin Paper
Appears in Collections:Volume 25, No. 45

Citable URI : http://hdl.handle.net/10069/14943

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