A ctenophore (comb jelly) employs vortex rebound dynamics and outperforms other gelatinous swimmers
A ctenophore (comb jelly) employs vortex rebound dynamics and outperforms other gelatinous swimmers
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DOI：
10.1098/rsos.181615
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发表时间：
2019-03-01
影响因子：
3.5
通讯作者：
Sutherland, Kelly R.
中科院分区：
文献类型：
--
作者：
Gemmell, Brad J.;Colin, Sean P.;Sutherland, Kelly R.
胶状浮游动物表现出广泛的推进游泳模式。其中最具能量效率的是许多种类的剑虫所表现出的划船行为，它们利用涡旋相互作用来实现这一结果。栉水母（栉水母）通常使用一种缓慢游动的、基于纤毛的推进方式。然而，cyropsis属的物种已经发展出一种额外的推进策略，即划船通常用于觅食的裂片，以便迅速逃离捕食者。在这项研究中，我们使用高速数字粒子图像测速来检查这种很少研究的推进机构的运动学和流体动力学。这种机制使cyropsis能够达到大小调节的速度，几乎是其他大型凝胶游泳者的两倍。对这种逃逸模式的流体动力学基础的研究揭示了以前没有在其他生物推进系统中描述过的新的涡旋相互作用。在逃逸游泳过程中，漩涡的排列产生了类似的结构和影响，就像研究得很好的“漩涡反弹”现象一样，当漩涡环接近固体壁面时，就会发生这种现象。这些结果扩展了我们对动物如何使用涡-涡相互作用的理解，并提供了重要的见解，可以为推进系统的生物工程提供信息。
Gelatinous zooplankton exhibit a wide range of propulsive swimming modes. One of the most energetically efficient is the rowing behaviour exhibited by many species of schyphomedusae, which employ vortex interactions to achieve this result. Ctenophores (comb jellies) typically use a slow swimming, cilia-based mode of propulsion. However, species within the genus Ocyropsis have developed an additional propulsive strategy of rowing the lobes, which are normally used for feeding, in order to rapidly escape from predators. In this study, we used high-speed digital particle image velocimetry to examine the kinematics and fluid dynamics of this rarely studied propulsive mechanism. This mechanism allows Ocyropsis to achieve size-adjusted speeds that are nearly double those of other large gelatinous swimmers. The investigation of the fluid dynamic basis of this escape mode reveals novel vortex interactions that have not previously been described for other biological propulsion systems. The arrangement of vortices during escape swimming produces a similar configuration and impact as that of the well-studied 'vortex rebound' phenomenon which occurs when a vortex ring approaches a solid wall. These results extend our understanding of how animals use vortex-vortex interactions and provide important insights that can inform the bioinspired engineering of propulsion systems.