4027 流れ方向強制振動並列二円柱からの渦放出の可視化観測(G05-6 物体まわりの流れ(1),G05 流体工学)  [in Japanese] 4027 The Visual Observation of Vortex Shedding from a Pair of In-Line Forced Oscillating Parallel Arranged Circular Cylinders  [in Japanese]

In this study, the flow features of vortex shedding from a pair of parallel arranged circular cylinders oscillating along the direction of the flow were observed by visualizing water flow experiment at the ranges of the frequency ratio f/f_K=0〜7, amplitude ratio 2a/d=0.25 and 0.5, gap ratio G/d=0.75 and 1.0 and Reynolds number Re=470〜490. It was obtained that result of the established wind tunnel test and the result of this water tank test agreed about the characteristics of vortex shedding when varying the distance of cylinder gap without cylinder oscillation. The variations of mean vortex shedding frequency from oscillating cylinder were investigated. As a result of the experiments, the occurrence of the lock-in phenomenon and its range were shown. It was obtained that the states of the interference flow at the time of lock-in by the cylinder oscillation.