Fish Frank E, Lauder George V
Department of Biology, West Chester University, West Chester, PA 19383, USA
Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA.
J Exp Biol. 2017 Dec 1;220(Pt 23):4351-4363. doi: 10.1242/jeb.149617.
Aquatic vertebrates display a variety of control surfaces that are used for propulsion, stabilization, trim and maneuvering. Control surfaces include paired and median fins in fishes, and flippers and flukes in secondarily aquatic tetrapods. These structures initially evolved from embryonic fin folds in fishes and have been modified into complex control surfaces in derived aquatic tetrapods. Control surfaces function both actively and passively to produce torque about the center of mass by the generation of either lift or drag, or both, and thus produce vector forces to effect rectilinear locomotion, trim control and maneuvers. In addition to fins and flippers, there are other structures that act as control surfaces and enhance functionality. The entire body can act as a control surface and generate lift for stability in destabilizing flow regimes. Furthermore, control surfaces can undergo active shape change to enhance their performance, and a number of features act as secondary control structures: leading edge tubercles, wing-like canards, multiple fins in series, finlets, keels and trailing edge structures. These modifications to control surface design can alter flow to increase lift, reduce drag and enhance thrust in the case of propulsive fin-based systems in fishes and marine mammals, and are particularly interesting subjects for future research and application to engineered systems. Here, we review how modifications to control surfaces can alter flow and increase hydrodynamic performance.
水生脊椎动物展示出多种用于推进、稳定、平衡和操纵的控制面。控制面包括鱼类的成对鳍和中央鳍，以及次生水生四足动物的鳍状肢和尾鳍。这些结构最初从鱼类胚胎的鳍褶进化而来，并在衍生的水生四足动物中演变成复杂的控制面。控制面通过产生升力或阻力，或两者兼而有之，围绕质心主动和被动地发挥作用以产生扭矩，从而产生矢量力来实现直线运动、平衡控制和操纵。除了鳍和鳍状肢外，还有其他结构可作为控制面并增强功能。整个身体可作为控制面，并在不稳定的流动状态下产生升力以保持稳定。此外，控制面可进行主动形状变化以提高其性能，并且一些特征可作为辅助控制结构：前缘瘤、翼状鸭翼、串联的多个鳍、小鳍、龙骨和后缘结构。对于鱼类和海洋哺乳动物中基于鳍推进的系统而言，这些对控制面设计的修改可改变水流，以增加升力、减少阻力并增强推力，并且是未来研究以及应用于工程系统的特别有趣的课题。在此，我们综述控制面的修改如何改变水流并提高水动力性能。
