FUNCTIONAL MORPHOLOGY AND HYDRODYNAMICS OF PLESIOSAUR NECKS: DOES SIZE MATTER?
FUNCTIONAL MORPHOLOGY AND HYDRODYNAMICS OF PLESIOSAUR NECKS: DOES SIZE MATTER?
复制标题
蛇颈龙颈部的功能形态和流体动力学：尺寸重要吗？
DOI：
10.1080/02724634.2019.1594850
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发表时间：
2019
影响因子：
1.4
通讯作者：
P. Falkingham
中科院分区：
文献类型：
--
作者：
P. Troelsen;D. Wilkinson;M. Seddighi;D. Allanson;P. Falkingham
摘要-蛇颈龙是中生代海洋爬行动物中一个神秘而多样的灭绝类群，以其独特的身体结构而闻名，有两对鳍状肢和通常细长的脖子。长脖子在进化枝中进化了几次，但进化优势还没有得到很好的理解。以前的研究主要集中在游泳速度或鳍状肢运动。本文采用基于雷诺平均纳维尔-斯托克斯（RANS）方法的计算流体动力学（CFD）模拟方法，对蛇颈龙颈部长度和厚度的流体动力学特性进行了研究。模拟了五种不同蛇颈龙模型周围形成的流型，三种不同的颈部长度（颈部/身体比为0.2，0.41和0.63）和两种不同的颈部厚度（与颈椎宽度相比增加了100%和343%）。通过模拟水流经过的三维数字蛇颈龙模型，我们的研究结果表明，颈部伸长并没有显着影响阻力所经历的向前游泳蛇颈龙。然而，与较细的颈部相比，较粗的颈部确实减少了阻力。在这项研究中使用的三个颈部长度所经历的一致的阻力系数表明，至少在1至10米/秒的速度向前运动，流体动力学的影响是不是一个限制选择压力的蛇颈龙长颈的演变。我们还测试了在向前运动过程中弯曲长颈的影响。蛇颈龙的颈部在侧屈时均匀弯曲，增加了垂直于水流的表面积，随后增加了拖曳力。这种影响在最长颈的形式中最为明显。
ABSTRACT —Plesiosaurs are an enigmatic, diverse extinct group of Mesozoic marine reptiles well known for their unique body plan with two pairs of flippers and usually an elongated neck. The long neck evolved several times within the clade, yet the evolutionary advantages are not well understood. Previous studies have mainly focused on swimming speeds or flipper locomotion. We evaluated the hydrodynamics of neck length and thickness in plesiosaurs using computational fluid dynamics (CFD) simulations based on the Reynolds-averaged Navier-Stokes (RANS) approach. Simulations were performed of flow patterns forming around five distinctive plesiosaur models, three of different neck lengths (neck/body ratios of 0.2, 0.41, and 0.63) and two of different neck thicknesses (100% and 343% increase compared with cervical vertebrae width). By simulating water flow past the three-dimensional digital plesiosaur models, our results demonstrated that neck elongation does not noticeably affect the force of drag experienced by forward-swimming plesiosaurs. Thicker necks did reduce drag compared with thinner necks, however. The consistent drag coefficient experienced by the three neck lengths used in this study indicates that, at least for forward motion at speeds from 1 to 10 m/s, hydrodynamic implications were not a limiting selective pressure on the evolution of long necks in plesiosaurs. We also tested the effects of bending the long neck during forward motion. Bending a plesiosaur neck evenly in lateral flexion increased the surface area normal to flow and subsequently increased drag force. This effect was most noticeable in the longest-necked forms.
加州海狮游泳：形态测量、阻力和能量。
DOI：
10.1242/jeb.131.1.117
发表时间：
1987
期刊：
The Journal of experimental biology
影响因子：
--
作者：
Feldkamp,SD
通讯作者：
Feldkamp,SD
长须鲸鳍状肢的水动力特性可预测最大滚动性能
DOI：
10.1242/jeb.137091
发表时间：
2016
期刊：
The Journal of Experimental Biology
影响因子：
--
作者：
Segre, Paolo S.;Cade, David E.;Fish, Frank E.;Potvin, Jean;Allen, Ann N.;Calambokidis, John;Friedlaender, Ari S.;Goldbogen, Jeremy A.
通讯作者：
Goldbogen, Jeremy A.
影响因子：
3.7
作者：
Dynowski JF;Nebelsick JH;Klein A;Roth-Nebelsick A
通讯作者：
Roth-Nebelsick A