Vertically clamped flexible flags in an oncoming Poiseuille flow were numerically modeled to investigate the hydrodynamic interaction and dynamics of the flexible flags using the immersed boundary method. The number of flags modeled was increased step by step: a single flag, double flags, triple flags, and a large array of multiple flags were modeled. The flexible flags displayed a flapping mode or a fully deflected mode, depending on the relationship between the elastic inner force and the hydrodynamic force. The bending angle (α), flapping amplitude (A), and period (T) of the single flag decreased as the bending rigidity (γ) increased. In the double and triple flag systems, the bending angle of the first flag reached a steady state as the gap distance (d) increased. The gap distance affected the position of the flag relative to the vortical structures. The vortical structures merged and formed a large vortex. Small vortical structures penetrated the large gap to drive flag flapping and force flag bending. In a large array of multiple flags, all flags were present in the fully deflected mode for a small gap distance. As the gap distance increased, the interactions between the flags increased. The flags were significantly influenced by the inlet and exit conditions.

中文翻译：

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在Poiseuille流中垂直夹紧的柔性标记

用浸入边界方法对进入的Poiseuille流中垂直夹紧的柔性标记进行了数值建模，以研究柔性标记的流体动力相互作用和动力学。建模的标志数量逐步增加：对单个标志，双标志，三重标志和大量的多个标志进行了建模。柔性标记根据弹性内力和流体动力之间的关系显示拍打模式或完全偏转模式。单个标志的弯曲角度（α），拍打幅度（A）和周期（T）随着弯曲刚度（γ）的减小而减小） 增加。在双标记和三标记系统中，第一标记的弯曲角度随着间隙距离（d）的增加而达到稳定状态。间隙距离影响标志相对于旋涡结构的位置。旋涡结构合并形成一个大旋涡。小型涡旋结构穿透了较大的缝隙，以驱动旗拍打和力旗弯曲。在由多个标志组成的大型阵列中，所有标志都以完全偏转的模式存在一段很小的间隙距离。随着间隙距离增加，标记之间的相互作用也增加。这些标志受进出条件的影响很大。