How zebrafish turn: analysis of pressure force dynamics and mechanical work
How zebrafish turn: analysis of pressure force dynamics and mechanical work
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DOI：
10.1242/jeb.223230
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发表时间：
2020-08-01
影响因子：
2.8
通讯作者：
Lauder, George, V
中科院分区：
文献类型：
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作者：
Thandiackal, Robin;Lauder, George, V
许多鱼类游得很稳定，而斑马鱼经常表现出不稳定的爆发和海岸游泳，其特点是反复转弯，然后是滑行周期。这样的行为提供了一个机会来研究这样的假设，即在转弯的早期阶段，接近最大体曲率的时候，负机械功发生在身体的后部区域。在这里，我们使用一种改进的粒子图像测速(PIV)技术来获得斑马鱼转弯过程中的高分辨率流场。使用详细的游泳运动学和体表压力计算，我们估计了流体-结构相互作用力，以及在转弯过程中沿身体的力和力矩模式。然后，我们计算了每个身体部分所做的机械功。我们使用身体上正负工作的估计模式来评估假设(基于鱼类中线运动学)，即身体后部区域将经历主要的负工作。10%-20%的机械功是由流体在身体上做的(负功)，负功集中在身体的前部和中部，而不是沿着尾部。通过考虑正负功之和，计算了转体的能量成本，并与以往鱼类转体能量的代谢估计进行了比较。本文提出的分析工作流程为量化鱼类运动的水动力学机制提供了一种严格的方法，并有助于理解身体运动学是如何在自由游泳的鱼类中产生运动力的。
Whereas many fishes swim steadily, zebrafish regularly exhibit unsteady burst-and-coast swimming, which is characterized by repeated sequences of turns followed by gliding periods. Such a behavior offers the opportunity to investigate the hypothesis that negative mechanical work occurs in posterior regions of the body during early phases of the turn near the time of maximal body curvature. Here, we used a modified particle image velocimetry (PIV) technique to obtain high-resolution flow fields around the zebrafish body during turns. Using detailed swimming kinematics coupled with body surface pressure computations, we estimated fluid-structure interaction forces and the pattern of forces and torques along the body during turning. We then calculated the mechanical work done by each body segment. We used estimated patterns of positive and negative work along the body to evaluate the hypothesis (based on fish midline kinematics) that the posterior body region would experience predominantly negative work. Between 10% and 20% of the total mechanical work was done by the fluid on the body (negative work), and negative work was concentrated in the anterior and middle areas of the body, not along the caudal region. Energetic costs of turning were calculated by considering the sum of positive and negative work and were compared with previous metabolic estimates of turning energetics in fishes. The analytical workflow presented here provides a rigorous way to quantify hydrodynamic mechanisms of fish locomotion and facilitates the understanding of how body kinematics generate locomotor forces in freely swimming fishes.