标题： 滞回现象在旗 instability 中的起源 显示英文标题

标题： The origin of hysteresis in the flag instability

摘要： 当一个柔性悬臂板浸入均匀气流中时，会发生拍打旗不稳定现象。至今，这种气动弹性不稳定性的一些非线性方面仍知之甚少。特别是，文献中的实验结果都报告了一个大的滞后回路，而在数值模拟中的分岔要么是超临界，要么是次临界，且滞后回路较小。本文解决了这一差异。首先，在细长体和二维极限条件下进行了弱非线性稳定性分析，其次对平板和曲板进行了新的实验。这种差异归因于实验中平板不可避免的平面度缺陷。 显示英文摘要

摘要： The flapping flag instability occurs when a flexible cantilevered plate is immersed in a uniform airflow. To this day, the nonlinear aspects of this aeroelastic instability are largely unknown. In particular, experiments in the literature all report a large hysteresis loop, while the bifurcation in numerical simulations is either supercritical or subcritical with a small hysteresis loop. In this paper, this discrepancy is addressed. First weakly nonlinear stability analyses are conducted in the slender-body and two-dimensional limits, and second new experiments are performed with flat and curved plates. The discrepancy is attributed to inevitable planeity defects of the plates in the experiments.