流れ方向に比較的大振幅低振動数で強制振動している柱状物体からの渦放出

抄録

Flow visualization observation was carried out for the aspect of the vortex flow when oscillating a cylinder with large amplitude low oscillation frequency comparatively supposing a pulsating flow using the closed circuit water channel by the tracer pouring streak method. The pulsating flow was produced by oscillating the cylinder in the direction of the flow by making main flow velocity into 0.0654 m/s. The used cylinders are two kinds of circular cylinders, a square cylinder and a bluff body, and those projection-width are 10mm and 16mm, 16.97mm and 15mm, respectively. Oscillating half amplitude is 40mm and oscillation frequency was gradually varied in 0 to 0.16Hz. As a result, it was shown by the existence of movement of the separating point that the aspects of the vortex shedding in one cycle of oscillation differ. The cylinder position when the vortex shedding is observed was investigated. When the velocity ratio became large, it became clear that the numbers of vortices at the time of acceleration and a slowdown differed.