Effects of Sway Motion and Flow-Induced Vibration on Vortex Structure Behind Flexible Rectangular Plate

Vortex structure behind a flexible rectangular plate with sway motion and flow-induced vibration was experimentally investigated by wind tunnel experiment by using Particle Image Velocimetry (PIV). The flexible rectangular plate, which was made of a polyurethane block, was cantilevered on a flat plate. On the opposite end, top free end showed a sway motion in the downstream direction. Increasing sway angle, the top free end involved the flow-induced in-line vibration which has a small amplitude. This is a typical example of fluid-structure interaction problem. However more experimental research for the effects of the sway motion and the flow-induced vibration on vortex structure behind the rectangular plate is required. In this paper, we focus attention on the phase-averaged vortex structure when the amplitude of vibration is the largest and smallest case. PIV measurement was conducted to clarify the phase-averaged and the instantaneous vortex structure behind the swaying plate. We discussed the effect of sway motion and flow-induced vibration on vortex structure.