トリッピングロッドによる円柱の流体力の抑制(流体工学,流体機械)

概要

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In this study, suppression of fluid forces, particularly fluctuating fluid forces, acting on a circular cylinder in uniform flow was investigated. Experiments were carried out with the Reynolds numbers fixed at 5.5×10^4, which is in the range of subcritical Reynolds numbers. Fluid forces acting on the circular cylinder was suppressed by setting two tripping rods in the neighborhood of the surface of the circular cylinder to control the flow over the surface of the cylinder. The angles at which the tripping rods were set were changed within the range of α=+20〜±60° from the stagnation point, and the ratio of tripping rod of diameter d to circular cylinder diameter D was changed within the range of d/D=0.08〜0.12. It was found that the largest reduction in fluid forces occurred when the tripping rods were set at angles in the range of α=30〜40°. In this condition, the time-averaged and fluctuating drag coefficients, C_D and C_<Df>, were decreased down to 73% and 64% respectively, and the fluctuating lift coefficients C_<Lf>, was decreased down to 87%. The generation of fluctuating lift associated with vortex shedding from the cylinder was suppressed almost completely in this condition.
一般社団法人日本機械学会の論文
2003-03-25