Hydrodynamic schooling of flapping swimmers.
Hydrodynamic schooling of flapping swimmers.
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DOI：
10.1038/ncomms9514
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发表时间：
2015-10-06
影响因子：
16.6
通讯作者：
Ristroph L
中科院分区：
文献类型：
--
作者：
Becker AD;Masoud H;Newbolt JW;Shelley M;Ristroph L
鱼群和鸟群是集体行为的迷人例子，其中许多个体产生复杂的流动并与之互动。受动物群体运动的启发，在这里，我们探讨了许多机构的运动是如何从它们的流动介导的相互作用中出现的。通过实验和模拟阵列的扑翼，在集体尾流推进，我们发现不同的模式，其特征在于组游泳速度和空间相移的轨迹之间的相邻的翅膀。对于相同的扑翼运动，慢模式和快模式共存，对应于建设性和破坏性的机翼尾流相互作用。仿真结果表明，群体游泳可以提高速度和节省电力，我们捕捉的关键现象，在一个数学模型的基础上记忆或存储和回忆的信息流场。这些结果还表明，流体动力学相互作用本身就足以产生连贯的集体运动，从而可能提出新的方法来表征流动在动物群体中的作用。自然界中动物的集群通常通过能量优化方法来解释。在这里，Becker等人模拟了水箱中无限多游泳者的条件，并表明仅流体动力学相互作用就足以导致连贯和集体运动。
Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing–wake interactions. Simulations show that swimming in a group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. These results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups. Schooling or flocking of animals in nature is generally explained via an energy optimization approach. Here, Becker et al. mimic the conditions for an infinite array of swimmers in a water tank and show that fluid dynamic interactions alone are sufficient to lead to coherent and collective locomotion.