PDF(Pubmed)
Abstract：
The ridges of the dermal denticles of migratory sharks have inspired riblets to reduce the frictional drag of a fluid. In particular, the dermal denticles of white sharks (Carcharodon carcharias) are characterized by a high middle ridge and low side ridges. The detailed morphology of their denticles and their variation along the body, however, have never been investigated. Moreover, the hydrodynamic function of high-low combinations of ridges is unknown. In this article, the ridge spacings and heights of the white shark denticles were three-dimensionally quantified using microfocus X-ray computed tomography. Then, the swimming speed at which the ridges would reduce drag was hydrodynamically calculated with a flat plate body model and previous riblet data. High ridges with a large spacing were found to effectively reduce drag at a migration speed of 2.3 m s-1, while adjacent high and low ridges with a small spacing reduced drag at a burst hunting speed of 5.1 m s-1. Moreover, the above hydrodynamic calculation method was also applied to the shortfin mako shark and an extinct giant shark (called megalodon) with known ridge spacings, resulting in the estimated hunting speeds of 10.5 m s-1and 5.9 m s-1, respectively.
摘要：
迁徙鲨鱼的真皮小齿的脊有灵感的肋骨，以减少流体的摩擦阻力。特别是,白鲨（Carcharodoncarcharharas）的真皮小齿的特征是中间脊高，侧面脊低。它们的细齿的详细形态及其沿身体的变化，然而,从未被调查过。此外，高低脊组合的流体动力学功能是未知的。在这篇文章中,使用微焦点X射线计算机断层扫描对白鲨齿的脊间距和高度进行了三维量化。然后，用平板体模型和先前的肋骨数据流体动力学计算了山脊减少阻力的游泳速度。发现间距大的高脊在2.3ms-1的迁移速度下有效地减少了阻力，而间距小的相邻的高脊和低脊在5.1ms-1的爆发狩猎速度下减少了阻力。此外，上述水动力计算方法也适用于已知脊间距的短鳍马科鲨和已灭绝的巨鲨(称为megalodon)，估计狩猎速度分别为10.5ms-1和5.9ms-1。
