リング状突起物により発生する管内流の乱流パフ(流体工学,流体機械)

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This paper describes the generation and growth of isolated turbulent puff, which is produced by a ring-shaped roughness element at the entrance region of a pipe flow. Flow visualization and LDV measurement were carried out using a straight glass tube of diameter D=5.02 mm and total length L=2712 mm. The roughness elements were installed at a downstream location of 77D from the entrance of the tube. The feature of the origin of turbulence, which is due to the separated flow on the leading edge of the roughness element, was photographed. It was found that, even if the intense turbulence is produced by the roughness element at a Reynolds number of 2100, the puff generates at a far downstream location at which the relaminarization of flow has considerably proceeded. It was also found that the equilibrium puff is achieved at a downstream distance of about 100D from the origin of the puff.
一般社団法人日本機械学会の論文
2002-02-25