AM05-04-015 乱流遷移を応用した矩形柱の抗力軽減(境界層とせん断流4,一般講演)

概要

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The reduction of drag of a rectangular cylinder with the width/height ratio c/d<0.5 of a section was investigated. The drag coefficient is very large from 2.0 to 2.5. To control the flow field around the rectangular cylinder, the both side surfaces are cutting out a circular arc. According to the previous paper, for the range of Reynolds number beyond 2.3x10^4, the shear layers separated from the front corners reattach circular arc of the cylinder. Then, the transition in the boundary layer and the turbulent separation occur. This turbulent transition was applied to the present rectangular cylinders of c/d=0.30, 0.39 and 0.47. The front face of a circular cylinder was cut at a circumferential 53deg and the rear face was cut at 90, 100, 110deg. As the results, the wake width decreases and the vortex formation region goes downstream. The Strouhal number increases beyond 0.24 and the base pressure coefficient rises. The drag coefficient of the rectangular cylinders with two circular arcs decreases by about half of the rectangular cylinder without circular arcs.
日本流体力学会の論文
2005-09-05