急縮小円管の流動抵抗低減に関する研究 : リング状小物体によるはく離流れの制御(流体工学,流体機械)

概要

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A flow through the circular pipe which has abrupt contraction has two distinguished vortex regions just before and after the contraction. The vortex at which latter position is cause to reduce the effective cross-sectional area of downstream pipe and to increase the flow resistance of this kind of pipe. In this study, we tried to reduce the flow resistance by mounting a small ring shaped obstacle upstream of contraction. As a result, it was made clear that the obstacle of height 0.4H (H: step height) makes flow resistance smaller, and optimal distance of the obstacle from contraction is about 1H. The unsteadiness properties of the vortex shedding from the edge of the contraction is also made clear.
一般社団法人日本機械学会の論文
2004-03-25