Body dynamics and hydrodynamics of swimming fish larvae: a computational study
Body dynamics and hydrodynamics of swimming fish larvae: a computational study
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DOI：
10.1242/jeb.071837
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发表时间：
2012-11-01
影响因子：
2.8
通讯作者：
Liu, Hao
中科院分区：
文献类型：
--
作者：
Li, Gen;Mueller, Ulrike K.;Liu, Hao
为了了解鱼游泳的机理，我们需要知道流体施加的力以及这些力是如何影响鱼的运动的。为此，我们开发了一种集流体力学和物体动力学于一体的三维计算方法。这项研究量化了一条游动的斑马鱼(Danio Rerio)幼体周围的流动。我们使用受精后3天和5天的实际鱼苗的形态和运动学数据作为计算模型的输入，该模型根据规定的身体形状变化来预测自由游泳的动力学。我们模拟了循环游泳和自发的C-Start。与二维粒子图像测速仪和运动学数据的严格比较表明，计算模型准确地预测了鱼的质心运动以及流动的空间和时间特征。压力和剪力沿身体的分布表明，推力主要产生在身体的后半部分。我们还探讨了体波幅度对游泳成绩的影响，考虑到波幅比实验观察值大或小40%。增加体波幅度，前向游泳速度从每秒7个体长提高到21个体长，这与实验观察一致。该模型还预测，当所需机械功率翻两番时，推进效率将从0.22非线性增加到0.32。当波幅高于实验参考值时，效率的提高很小，而运输成本却显著增加。
To understand the mechanics of fish swimming, we need to know the forces exerted by the fluid and how these forces affect the motion of the fish. To this end, we developed a 3-D computational approach that integrates hydrodynamics and body dynamics. This study quantifies the flow around a swimming zebrafish (Danio rerio) larva. We used morphological and kinematics data from actual fish larvae aged 3 and 5 days post fertilization as input for a computational model that predicted free-swimming dynamics from prescribed changes in body shape. We simulated cyclic swimming and a spontaneous C-start. A rigorous comparison with 2-D particle image velocimetry and kinematics data revealed that the computational model accurately predicted the motion of the fish's centre of mass as well as the spatial and temporal characteristics of the flow. The distribution of pressure and shear forces along the body showed that thrust is mainly produced in the posterior half of the body. We also explored the effect of the body wave amplitude on swimming performance by considering wave amplitudes that were up to 40% larger or smaller than the experimentally observed value. Increasing the body wave amplitude increased forward swimming speed from 7 to 21 body lengths per second, which is consistent with experimental observations. The model also predicted a non-linear increase in propulsive efficiency from 0.22 to 0.32 while the required mechanical power quadrupled. The efficiency increase was only minor for wave amplitudes above the experimental reference value, whereas the cost of transport rose significantly.