Thandiackal Robin, White Carl H, Bart-Smith Hilary, Lauder George V
Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
Bio-Inspired Engineering Research Laboratory (BIERL), Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer's Way, Charlottesville, VA 22903, USA.
Proc Biol Sci. 2021 Feb 24;288(1945):20202726. doi: 10.1098/rspb.2020.2726. Epub 2021 Feb 17.
Fish routinely accelerate during locomotor manoeuvres, yet little is known about the dynamics of acceleration performance. Thunniform fish use their lunate caudal fin to generate lift-based thrust during steady swimming, but the lift is limited during acceleration from rest because required oncoming flows are slow. To investigate what other thrust-generating mechanisms occur during this behaviour, we used the robotic system termed Tunabot Flex, which is a research platform featuring yellowfin tuna-inspired body and tail profiles. We generated linear accelerations from rest of various magnitudes (maximum acceleration of [Formula: see text] at [Formula: see text] tail beat frequency) and recorded instantaneous electrical power consumption. Using particle image velocimetry data, we quantified body kinematics and flow patterns to then compute surface pressures, thrust forces and mechanical power output along the body through time. We found that the head generates net drag and that the posterior body generates significant thrust, which reveals an additional propulsion mechanism to the lift-based caudal fin in this thunniform swimmer during linear accelerations from rest. Studying fish acceleration performance with an experimental platform capable of simultaneously measuring electrical power consumption, kinematics, fluid flow and mechanical power output provides a new opportunity to understand unsteady locomotor behaviours in both fishes and bioinspired aquatic robotic systems.
鱼类在运动 maneuvers 过程中经常加速，但对加速性能的动力学了解甚少。新月形尾鳍鱼类在稳定游泳时利用其新月形尾鳍产生基于升力的推力，但在从静止状态加速时升力有限，因为所需的迎面水流较慢。为了研究在这种行为过程中还会出现哪些其他推力产生机制，我们使用了名为 Tunabot Flex 的机器人系统，它是一个具有受黄鳍金枪鱼启发的身体和尾部轮廓的研究平台。我们从静止状态产生了各种大小的线性加速度（在[公式：见文本]尾拍频率下最大加速度为[公式：见文本]），并记录了瞬时电功率消耗。利用粒子图像测速数据，我们量化了身体运动学和流动模式，然后计算了随时间沿身体的表面压力、推力和机械功率输出。我们发现头部产生净阻力，而后部身体产生显著的推力，这揭示了这种新月形游泳者在从静止状态进行线性加速时，除了基于升力的尾鳍之外的另一种推进机制。使用一个能够同时测量电功率消耗、运动学、流体流动和机械功率输出的实验平台来研究鱼类的加速性能，为理解鱼类和受生物启发的水生机器人系统中的非稳定运动行为提供了新的机会。
