Flutter generated on a sheet in 3D flow: influence of aspect ratio of sheets on post-critical and hysteretic behavior

Thin flexible sheets are utilized in numerous engineering applications. In the manufacturing process, the sheets are supported in fluid flow. Then, flutter is generated on the sheet, which results in serious quality defects (wrinkle etc.). Thus, understanding of the flutter characteristics is quite important to prevent these serious defects. In this study, the influence of the aspect ratio of sheets on the post-critical behavior, e.g. flutter amplitude and hysteretic behavior, is investigated by nonlinear numerical simulations and wind-tunnel experiments. As a result of calculations and experiments focused on the aspect ratio, the critical flutter velocity tends to increase as the aspect ratio is decreased owing to the three-dimensionality of the fluid flow. The flutter amplitude increases with increasing aspect ratio. Moreover, no hysteretic behavior is observed regardless of the aspect ratio for a relatively small mass ratio. In contrast, hysteretic behavior is generated with a large aspect ratio for large enough mass ratios.