On the Flow Around Flexible Plates, Oscillating with Large Amplitude

Quasi-two-dimensional flows around the free ends of a flexible single plate and two plates, both oscillating with large amplitude, were studied by flow visualization experiments and numerical simulations. The smoke wire method was employed in experiments, and the discrete vortex method combined with the singularity method was employed in numerical simulations. In the case of the two plates, the effects of the distances between two plates on the flow structure were investigated for oscillations in-phase and in counter-phase. Tracer particle movements in numerical simulations were found to be sensibly coincident with those in the flow visualization experiments. It was also demonstrated that, for counter-phase oscillation, the normal flow in the downstream direction was greatly affected by the distance between the two plates, but that such flow was scarcely affected for in-phase oscillation. Moreover, details of the flow field around the free ends of the plates, particularly the generation of free vortices, their movements and the induced velocity during one cycle, are described.