Airfoil-like mechanics generate thrust on the anterior body of swimming fishes
Airfoil-like mechanics generate thrust on the anterior body of swimming fishes
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DOI：
10.1073/pnas.1919055117
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发表时间：
2020-05-12
影响因子：
11.1
通讯作者：
Tytell, Eric D.
中科院分区：
文献类型：
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作者：
Lucas, Kelsey N.;Lauder, George V.;Tytell, Eric D.
许多鱼类的前体形状像侧转的机翼。由于与游泳方向成摆动角度，这种翼型由于其形状和俯仰运动而承受负压。该负压充当前体上的推力。在这里，我们应用高分辨率、基于压力的方法来描述两种鱼，翻车鱼（Lepomis Macrochirus Rafinesque）和溪鳟鱼（Salvelinus fontinalis Mitchill），如何以最常见的鱼类游泳模式——鲹形模式游泳，利用前沿吸力力学（很像机翼）在其前体上产生推力。这些机制与之前报道的七鳃鳗（鳗状游泳者）的机制形成鲜明对比，七鳃鳗在负压下产生推力，但通过波动机制产生推力。通过负压作用在这些车状游泳者前体上的推力占身体和尾鳍产生的总推力的 28%，大大减少了前体上的净阻力。在后部区域，身体形状和运动学的细微差异使鳟鱼比翻车鱼产生更多的推力，这表明它们可能更有效地游泳。尽管这些物种之间的系统发育距离很大，并且尾部附近存在差异，但前体周围的压力分布是相似的。我们认为这种类似机翼的力学是非常有效的，因为它们需要很少的运动，因此相对较少的主动肌肉能量，并且可以被广泛的鱼类使用，因为许多物种具有适当形状的身体。
The anterior body of many fishes is shaped like an airfoil turned on its side. With an oscillating angle to the swimming direction, such an airfoil experiences negative pressure due to both its shape and pitching movements. This negative pressure acts as thrust forces on the anterior body. Here, we apply a high-resolution, pressurebased approach to describe how two fishes, bluegill sunfish (Lepomis macrochirus Rafinesque) and brook trout (Salvelinus fontinalis Mitchill), swimming in the carangiform mode, the most common fish swimming mode, generate thrust on their anterior bodies using leading-edge suction mechanics, much like an airfoil. These mechanics contrast with those previously reported in lampreys-anguilliform swimmers-which produce thrust with negative pressure but do so through undulatory mechanics. The thrust produced on the anterior bodies of these carangiform swimmers through negative pressure comprises 28% of the total thrust produced over the body and caudal fin, substantially decreasing the net drag on the anterior body. On the posterior region, subtle differences in body shape and kinematics allow trout to produce more thrust than bluegill, suggesting that they may swim more effectively. Despite the large phylogenetic distance between these species, and differences near the tail, the pressure profiles around the anterior body are similar. We suggest that such airfoil-like mechanics are highly efficient, because they require very little movement and therefore relatively little active muscular energy, and may be used by a wide range of fishes since many species have appropriately shaped bodies.