Hydrodynamic considerations for multiple fin interactions in rapid maneuvers

任何生物体的跳跃都需要爆发力和肌肉协调性。水上空对空跳伞运动员必须产生足够的推力，以应对离开水面时流体密度的急剧下降，从而产生力量的能力。跳跃表示在有限的空间（单个身体长度）中以有限的持续时间（直到身体离开水）进行短爆发机动。本研究将探讨箭鱼在短距离、有限空间、快速跳跃及游动动作时多鳍间的互动。弓箭鱼是一种独特的鱼类，它使用多个鳍从静止的瞄准位置快速跳出水面。跳跃行为的分析，在一个受控的实验室环境中，并与在水中演习的比较，可以产生有价值的水动力学洞察到多鳍相互作用的范围内快速游泳行为。协调的鳍运动被认为可以增强推力，增加稳定性，并在快速机动时帮助瞄准。了解复杂的多鳍游泳策略可以帮助生物启发游泳机器人设计？其中可以采用多个翼片来增加飞行器在狭窄空间中的机动性或允许受控的出水机动。 本文确定的协同多推进器关系可能是未来仿生水上和空中水上交通工具设计的范式转变。几个关键的假设将被考虑：（1）尾部运动学弓箭鱼跳跃调整特定的跳跃高度;（2）第二鳍显着提高跳跃推力和身体的稳定性，在快速机动;（3）跳跃是一个充满活力的可行的猎物捕捉策略在竞争环境中。鳍运动和流体流动的高速成像将被用来开发一个水动力学模型的推力生产在跳跃和最大动物跳跃高度，这是一个可控的性能变量在实验室之间的关系。合成孔径粒子图像测速技术是一种定量的三维流场成像技术，用于测量近体速度场。弓箭鱼是研究的模式鱼类，因为它们使用多个鳍协同快速跳出水面，在跳跃开始时没有任何向上的速度。弓箭手鱼跳让我们看到鱼产生的推进力和动量，以及水动力学？特别是达到最后跳跃高度所需的动能（即势能）？以更好地理解海对空撤离的未探索范例。弓箭鱼的独特形态，在尾部尾部前面有更大的尾鳍（背鳍和臀鳍），可能会增加整体推进效率和推力产生。跳跃机动和水中机动可以进行比较，以进一步了解多个鳍尾相互作用在快速和非定常游泳行为中的总体作用。快速爆发跳跃过程中鳍-鳍相互作用的特征有助于生物和进化生物学社区更好地理解鱼类游泳中的多鳍功能。拟议的STEM外展活动通过编程和动手实验数据处理让学生参与流体物理和生物启发设计;这些活动可扩展并可移植到更大的K-12 STEM社区。该项目的结果将在同行评审的期刊和流体动力学和有机体生物学社区的会议上传播。

Jumping by any organism requires high bursts of power and muscular coordination. Aquatic water-to-air jumpers must produce enough thrust to account for the drastic drop in fluid density, and thus force-producing ability, when exiting the water. Jumps represent short burst maneuvers in a restricted space (a single body length) with finite duration (until the body has exited the water). This work will investigate multi-fin interactions during short distance, confined space, rapid jumping and swimming maneuvers in archer fish. The archer fish is a unique fish species that uses multiple fins in concert to rapidly jump out of the water from a stationary aiming position. The analysis of jumping behaviors, in a controlled laboratory environment, and comparison with in-water maneuvers, can yield valuable hydrodynamic insight into multi-fin interactions for a range of rapid swimming behaviors. Coordinated fin motions are thought to enhance thrust, increase stability and aid in aiming during rapid maneuvers. Understanding complex multi-fin swimming strategies can help inform bio-inspired swimming robot designs ? where multiple fins could be employed to increase vehicle maneuverability in tight spaces or allow for controlled water-exit maneuvers. Synergistic multi-propulsor relationships identified herein could be paradigm-shifting for the design of future bioinspired aquatic and aerial-aquatic vehicles. Several key hypotheses will be considered: (1) tail kinematics during archer fish jumping are tuned for specific jump heights; (2) secondary fins significantly enhance jump thrust and body stability during rapid maneuvers; (3) jumping is an energetically viable prey capture strategy in competitive environments. High-speed imaging of fin motions and fluid flows will be used to develop a hydrodynamic model for the relationship between thrust production during a jump and maximum animal jump height, which is a controllable performance variable in the laboratory. Synthetic aperture particle image velocimetry, a quantitative three-dimensional imaging technique for flow field velocimetry, will measure the near body velocity fields. Archer fish are a model fish species to investigate, as they use multiple fins in concert to rapidly jump out of the water without any upwards velocity at jump initiation. The archer fish jump allows us to look at propulsive forces and momentum generated by the fish, as well as the hydrodynamic energetics ? specifically the kinetic energy required to reach the final jump height (i.e. potential energy) ? to better understand the unexplored paradigm of sea-to-air exit. The unique morphology of the archer fish, with larger aft fins (dorsal and anal fins) just in front of the caudal tail, potentially adds both to the overall propulsive efficiency and thrust production. Jump maneuvers and in-water maneuvers can be compared for further understanding of the overarching role of multiple fin wake interactions in rapid and unsteady swimming behaviors. The characterization of fin-fin interactions during rapid burst jumping helps the organismal and evolutionary biology communities better understand multi-fin function in fish swimming. The proposed STEM outreach activities engage students in fluid physics and bioinspired design, through programming and hands-on experimental data processing; these activities are scalable and portable to the larger K-12 STEM community. Results of the project will be disseminated in peer-reviewed journals and at conferences in both the fluid dynamic and organismal biology communities.