直交流中の円管群の流力振動に関する研究 : 比較的まばらに配置された円管群に作用する流体励振力の測定(機械力学,計測,自動制御)

概要

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The local fluid excitation force acting on a rotated square tube bundle having transverse pitch to diameter ratio of T/D=3.1, in a single-phase cross flow was measured, and the Normalized Power Spectral Density (NPSD) and the correlation length in the axial direction of a tube were examined. The fluid excitation force acting on the interior tube was from 3 times to 10 times larger than that acting on the upstream tube. The fluid force was almost fully developed after the third row. NPSD of the fluid excitation force could be almost plotted on a single universal curve. Regarding the lift direction, there was a peak in NPSD at fD/u〜O.3 caused by vortex shedding. Regarding the drag direction, there could be another peak in NPSD around twice the vortex shedding frequency. In the region of fD/u >0.5 where the effect of the vortex shedding was assumed to be small in the lift direction, the correlation length of the lift direction was approximately 1.1D. When vibration displacement amplitude was estimated using above mentioned NPSD and correlation length, they were proportional to around the third power of flow velocity.
社団法人日本機械学会の論文
2002-11-25