Surprising behaviors in flapping locomotion with passive pitching
Surprising behaviors in flapping locomotion with passive pitching
复制标题
DOI：
10.1063/1.3383215
复制
发表时间：
2010-04
影响因子：
4.6
通讯作者：
S. Spagnolie;Lionel Moret;M. Shelley;Jun Zhang
中科院分区：
文献类型：
--
作者：
S. Spagnolie;Lionel Moret;M. Shelley;Jun Zhang
为了更好地理解翅膀和鳍的柔韧性在扑翼运动中的作用，我们通过实验和数值模拟研究了一个在流体中主动上下摆动时能够被动“俯仰”的自由运动的翅膀。我们观察到一系列与较大水平速度相对应的扑翼频率，一个相对于固定（无俯仰）扑翼性能欠佳的区域，以及一个令人惊讶的滞后区域，在该区域中扑翼能够向任一方向水平移动（尽管特定的俯仰模式打破了左右对称性）。当扑翼频率接近浸没系统的共振频率时，水平速度达到峰值。与固定的翅膀不同，我们发现即使只有最微小的俯仰柔韧性，垂直扑动的对称翅膀也能实现运动，并且该系统呈现出与斯托克斯区域的持续偏离。垂直上下摆动运动和随之产生的俯仰之间的相位差随着……而连续变化。
To better understand the role of wing and fin flexibility in flapping locomotion, we study through experiment and numerical simulation a freely moving wing that can “pitch” passively as it is actively heaved in a fluid. We observe a range of flapping frequencies corresponding to large horizontal velocities, a regime of underperformance relative to a clamped (nonpitching) flapping wing, and a surprising, hysteretic regime in which the flapping wing can move horizontally in either direction (despite left/right symmetry being broken by the specific mode of pitching). The horizontal velocity is shown to peak when the flapping frequency is near the immersed system’s resonant frequency. Unlike for the clamped wing, we find that locomotion is achieved by vertically flapped symmetric wings with even the slightest pitching flexibility, and the system exhibits a continuous departure from the Stokesian regime. The phase difference between the vertical heaving motion and consequent pitching changes continuously with ...