论文标题
波长如何影响两个加速镜子对称纤细的游泳者的流体动力性能
How wavelength affects the hydrodynamic performance of two accelerating mirror-symmetric slender swimmers
论文作者
论文摘要
鱼类学校能够同时进行线性加速。为了揭示潜在的流体动力机制，我们从数值上研究了雷诺数字$ re = 1000-2000 $，strouhal数量$ s $ st = 0.2-0.7 $和波长$λ= 0.5-2 $影响均值净推力和净推力的均值净推力和净净推力效率，这是抗恒定中的两侧水电起伏。总共使用沉浸式边界方法模拟$ 550 $的情况。随着波长和曲线数的增加，推力显着增加，但在雷诺数的数字中仅略有略有增加。我们应用符号回归算法来建立这种关系。此外，我们发现镜像对称的教育可以实现\ textit {net}的推动力，是单个游泳者的十倍以上，尤其是在低雷诺数字上。最高效率是在$ st = 0.5 $和$λ= 1.2 $中获得的，其中$ st $与线性加速的天然游泳者中观察到的$ st $是一致的。确定了六个不同的流量结构。最高推力对应于不对称的流动模式，而当流动与收敛的涡流街道对称时，则会发生最高效率。
Fish schools are capable of simultaneous linear acceleration. To reveal the underlying hydrodynamic mechanism, we numerically investigate how Reynolds number $ Re = 1000 - 2000 $, Strouhal number $ St = 0.2 - 0.7 $ and wavelength $ λ= 0.5 - 2 $ affect the mean net thrust and net propulsive efficiency of two side-by-side hydrofoils undulating in anti-phase. In total, $ 550 $ cases are simulated using immersed boundary method. The thrust increases significantly with wavelength and Strouhal number, yet only slightly with the Reynolds number. We apply a symbolic regression algorithm to formulate this relationship. Furthermore, we find that mirror-symmetric schooling can achieve a \textit{net} thrust more than ten times that of a single swimmer, especially at low Reynolds numbers. The highest efficiency is obtained at $ St = 0.5 $ and $ λ= 1.2 $, where $ St $ is consistent with that observed in the linear-accelerating natural swimmers, \eg Crevalle jack. Six distinct flow structures are identified. The highest thrust corresponds to an asymmetric flow pattern, whereas the highest efficiency occurs when the flow is symmetric with converging vortex streets.
