Collective locomotion of two closely spaced self-propelled flapping plates
Collective locomotion of two closely spaced self-propelled flapping plates
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两个紧密间隔的自走式扑板的集体运动
DOI：
10.1017/jfm.2018.447
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发表时间：
2018-06
影响因子：
3.7
通讯作者：
Lu Xi-Yun
中科院分区：
文献类型：
--
作者：
Peng Ze-Rui;Huang Haibo;Lu Xi-Yun
精力充沛和绩效提高被认为是集体行为最令人着迷的成就之一，例如鱼群和飞行编队。对最初并排布置的两个自走式扑板的集体运动进行了数值研究。考虑两个板的同相和反相振荡。研究发现，由于流介导的相互作用，板会自发地形成一些稳定的构型，特别是同相情况下的交错跟随（SF）模式和交替领先（AL）模式以及反相情况下的并列移动（MA）模式和AL模式。在SF模式下，后板跟随前板，呈交错配置。在 AL 模式下，板交替并排互相追逐。在推进速度和效率方面，小横向间距$H$的SF模式下的板片性能优于串联跟随情况（$H=0$）和并排情况（即AL模式）。为了获得更高的推进效率，无论同相或反相振荡，两片具有适中弯曲刚度的板，例如$K\approx O(1)$ 是首选，并且它们应该在横向上足够接近。对于并排配置，与隔离板相比，每个板在反相和同相情况下的性能分别增强和减弱。除了压力和涡度等值线之外，还分析了作用在板上的法向力和推力。结果表明，推力主要由中等弯曲刚度下的法向力贡献。法向力和推力对于推进速度和效率至关重要。对于两个自推进板，考虑到流体动力学，为了获得更高的性能，并排配置中的同相SF模式和反相扑动是优选的。
Energetic benefit and enhanced performance are considered among the most fascinating achievements of collective behaviours, e.g. fish schools and flying formations. The collective locomotion of two self-propelled flapping plates initially in a side-by-side arrangement is investigated numerically. Both in-phase and antiphase oscillations for the two plates are considered. It is found that the plates will spontaneously form some stable configurations as a result of the flow-mediated interaction, specifically, the staggered-following (SF) mode and the alternate-leading (AL) mode for the in-phase scenario and the moving abreast (MA) mode and the AL mode for the antiphase scenario. In the SF mode, the rear plate follows the front one with a staggered configuration. In the AL mode, the plates chase each other side-by-side alternately. In terms of propulsive speed and efficiency, the performance of the plates in the SF mode with small lateral spacing $H$ is found to be better than those in the tandem following case ( $H=0$ ) and the side-by-side case (i.e. the AL mode). To achieve higher propulsive efficiency, no matter in-phase or antiphase oscillations, the two plates with moderate bending stiffness, e.g. $K\approx O(1)$ , are preferred and they should be close enough in the lateral direction. For the side-by-side configuration, the performance of each plate in the antiphase and in-phase scenarios is enhanced and weakened in comparison with that of the isolated plate, respectively. Besides the pressure and vorticity contours, the normal force and thrust acting on the plates are also analysed. It is revealed that the thrust is mainly contributed by the normal force at moderate bending stiffness. The normal force and thrust are critical to the propulsive speed and efficiency. For two self-propelled plates, in view of hydrodynamics, to achieve higher performance the in-phase SF mode and antiphase flappings in the side-by-side configuration are preferred.
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影响因子：
3.7
作者：
Li, Gao-Jin;Lu, Xi-Yun
通讯作者：
Lu, Xi-Yun
影响因子：
16.6
作者：
Becker AD;Masoud H;Newbolt JW;Shelley M;Ristroph L
通讯作者：
Ristroph L
DOI：
--
发表时间：
2008-03
期刊：
Bulletin of the American Physical Society
影响因子：
--
作者：
D. Saintillan
通讯作者：
D. Saintillan
影响因子：
2
作者：
D. Hummel
通讯作者：
D. Hummel
影响因子：
3.7
作者：
R. C. Mysa;K. Venkatraman
通讯作者：
R. C. Mysa;K. Venkatraman