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No. 42 (1991/09) >

 
Title :スプリットフィルムプローブによる後方ステップ流れの研究
Title alternative :A Study of Backward Facing Step Flow Using a Split Film Probe
Authors :照屋, 功
日下部, 純二
山里, 栄昭
伊良部, 邦夫
Authors alternative :Teruya, Isao
Kusakabe, Junji
Yamazato, Eisho
Irabu, Kunio
Issue Date :Sep-1991
Abstract :Reattachment of a turbulent shear layer is an important process in wide variety of engineering systems. A few examples of such systems arc diffusers, airfoils with separation bubbles, sudden area expansion in pipes or ducts, buildings and fences. Comparison of experimental data and evaluation of previous works on this subject are complicated by lack of instruments reliable in the separation regions. In this paper, an experiment was conducted employing a split film probe in the backward facing step which has large expansion ratio and high Reynolds number. A split film probe can measure the instantaneous magnitude and direction of the velocity in the separation region. From these measurement data, time-mean velocity profiles, turbulence intensities and forward flow fraction were evaluated. The experimental results brought out several features of the complex separation-reattachment process. Free shear layer was fully developed upstream of time-mean reattachment point. The maximum root-mean-squares of longitudinal velocity and of lateral velocity were about 0.22 and 0.14 at about x/x_R=0.6 and 0.8 respectively, where x is the longitudinal distance and x_R is the time-mean reattachment length. Unsteady reversing flow fraction still extended beyond time-mean reattachment point.
Type Local :紀要論文
ISSN :0389-102X
Publisher :琉球大学工学部
URI :http://hdl.handle.net/20.500.12000/1999
Citation :琉球大学工学部紀要 no.42 p.1 -8
Appears in Collections:No. 42 (1991/09)

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