Paniccia Damiano, Padovani Luca, Graziani Giorgio, Lugni Claudio, Piva Renzo
Department of Mechanical and Aerospace Engineering, Sapienza University, 00184 Rome, Italy.
Leonardo S.p.A., Piazza Monte Grappa 4, 00195 Rome, Italy.
Biomimetics (Basel). 2023 Sep 1;8(5):401. doi: 10.3390/biomimetics8050401.
The recoil motions in free swimming, given by lateral and angular rigid motions due to the interaction with the surrounding water, are of great importance for a correct evaluation of both the forward locomotion speed and efficiency of a fish-like body. Their contribution is essential for calculating the actual movements of the body rear end whose prominent influence on the generation of the proper body deformation was established a long time ago. In particular, the recoil motions are found here to promote a dramatic improvement of the performance when damaged fishes, namely for a partial functionality of the tail or even for its complete loss, are considered. In fact, the body deformation, which turns out to become oscillating and symmetric in the extreme case, is shown to recover in the water frame a kind of undulation leading to a certain locomotion speed though at the expense of a large energy consumption. There has been a deep interest in the subject since the infancy of swimming studies, and a revival has recently arisen for biomimetic applications to robotic fish-like bodies. We intend here to apply a theoretical impulse model to the oscillating fish in free swimming as a suitable test case to strengthen our belief in the beneficial effects of the recoil motions. At the same time, we intend to exploit the linearity of the model to detect from the numerical simulations the intrinsic physical reasons related to added mass and vorticity release behind the experimental observations.
自由游动时的反冲运动，由与周围水体相互作用产生的横向和角向刚体运动给出，对于正确评估类鱼身体的前进运动速度和效率非常重要。它们的贡献对于计算身体后端的实际运动至关重要，而身体后端对适当身体变形的产生具有显著影响这一点早在很久以前就已确立。特别地，在此发现当考虑受损鱼类时，即对于尾巴部分功能丧失甚至完全失去的情况，反冲运动能显著提升性能。事实上，在极端情况下会变成振荡且对称的身体变形，在水参考系中被证明能恢复一种波动，从而产生一定的运动速度，尽管代价是大量的能量消耗。自游泳研究初期以来，人们就对该主题有着浓厚的兴趣，并且最近在将其应用于仿鱼机器人身体的仿生学领域又重新兴起。我们在此打算将一个理论冲量模型应用于自由游动的振荡鱼，作为一个合适的测试案例，以增强我们对反冲运动有益效果的信心。同时，我们打算利用该模型的线性特性，从数值模拟中检测与附加质量和涡度释放相关的内在物理原因，这些原因是实验观测结果背后的因素。
