円柱に働く抗力の軽減に関する研究 : 第2報,レイノルズ数の影響

概要

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In order to reduce the drag of a circular cylinder in an uniform stream, a small rod was set upstream of the cylinder. The effect of the Rynolds number on drag reduction of the cylinder was investigated. The drag depends on the ratio of the rod to the cylinder diameter d/D, the distance between the axes of the rod and the cylinder L/D and the Reynolds number Re. Generally, the higher the Reynolds number, the greater the reduction of drag. The optimum conditions of drag reduction are clarified : for Re<4.1×10^4, d/D=0.25 and L/D=2.0, and for Re≧4.1×10^4, d/D=0.25 and L/D=1.75. Both are cases without vortex shedding from the rod. The drag with the rod compared to that without the rod decreases by 17% at Re=1.5×10^4 and 63% at Re=6.2×10^4.
一般社団法人日本機械学会の論文
1995-06-25