Locomotor function of the dorsal fin in rainbow trout: kinematic patterns and hydrodynamic forces
Locomotor function of the dorsal fin in rainbow trout: kinematic patterns and hydrodynamic forces
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DOI：
10.1242/jeb.01922
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发表时间：
2005-12-01
影响因子：
2.8
通讯作者：
Lauder, GV
中科院分区：
文献类型：
--
作者：
Drucker, EG;Lauder, GV
在这项研究中，我们研究了软背鳍的运动学和流体动力学在一个具有代表性的基础硬骨鱼，虹鳟鱼（Oncorhynchus mykiss），在稳定的直线运动在0.5-2.0体长（L）s（-1）和机动。在稳定游泳过程中，背鳍高度和后掠幅度随着速度的增加而减小。在水平面内观察时，背鳍尾流由机身两侧的成对涡（0.5 L s（-1））或机身上方的近线性排列的涡中心（1.0 L s（-1））组成，中心射流主要指向横向（横向：推力比=5-6）。在2.0 L s（-1）时，背鳍不再被用来增加尾流的动量。这种模式的鳟鱼背鳍在推力生产中的参与减少，随着速度的增加，与我们以前的研究结果的太阳鱼（Lepomis），这是流体动力学不活跃，在低速和脱落的推进涡尾在较高的速度软背鳍形成对比。鳟鱼的偏航动作涉及背鳍产生的一个涡环，它具有几乎直接侧向的强射流。在稳定的游泳过程中，由背鳍的旋涡尾流和脂肪鳍的非旋涡（阻力）尾流的尾部拦截被假设为增强尾部推力的机制。这项研究提供了第一个实验证据，准形软背鳍鳍的鳍作为一个辅助发电机在轴向运动。我们建议，区分中间和成对的鳍（MPF）的推进和身体和尾鳍（BCF）的推进鱼类之间经常模糊的重要作用，多个推进器在协调的方式行事。使用前中鳍振荡和轴向波动的组合，没有连续的成对鳍偏移，鳟鱼采用“M-BCF”步态在稳定的游泳。鳟鱼背鳍力的主要横向取向引起相应的滚动和偏航力矩，这必须由来自尾鳍、臀鳍和成对鳍的力来抵消。因此，鳟鱼的运动涉及同时使用多个鳍，大概是为了在环境扰动面前保持身体稳定。
In this study, we examine the kinematics and hydrodynamics of the soft dorsal fin in a representative basal teleost, the rainbow trout (Oncorhynchus mykiss), during steady rectilinear locomotion at 0.5-2.0 body lengths (L) s(-1) and during maneuvering. During steady swimming, dorsal fin height and sweep amplitude decrease with increasing speed. The dorsal fin wake, as viewed within a horizontal plane, consists of paired vortices on each side of the body (0.5 L s(-1)) or nearly linearly arrayed vortex centers above the body (1.0 L s(-1)) with central jet flows directed predominately laterally (lateral:thrust force ratio=5-6). At 2.0 L s(-1), the dorsal fin is no longer recruited to add momentum to the wake. This pattern of decreasing involvement of the trout dorsal fin in thrust production with increasing speed contrasts with the results of our previous study of the soft dorsal fin of sunfish (Lepomis), which is hydrodynamically inactive at low speed and sheds a propulsive vortex wake at higher speed. Yawing maneuvers by trout involve unilateral production of a single vortex ring by the dorsal fin with a strong jet flow oriented almost directly laterally. During steady swimming, interception by the tail of the dorsal fin's vortical wake and the adipose fin's non-vortical (drag) wake is hypothesized as a mechanism for enhancing tail thrust. This study provides the first experimental evidence that the plesiomorphic soft dorsal fin of ray-finned fishes acts as an ancillary force generator during axial locomotion. We suggest that the distinction often made between median and paired fin (MPF) propulsion and body and caudal fin (BCF) propulsion in fishes obscures the important role of multiple propulsors acting in a coordinated fashion. Using a combination of anterior median fin oscillation and axial undulation, without continuous paired fin excursions, trout employ an 'M-BCF' gait during steady swimming. The primarily lateral orientation of dorsal fin force in trout induces corresponding roll and yaw moments, which must be countered by forces from the caudal, anal and paired fins. Locomotion in trout therefore involves the simultaneous active use of multiple fins, presumably to maintain body stability in the face of environmental perturbations.