Accurate estimates of drag on marine animals are required to investigate the locomotive cost, propulsive efficiency, and the impacts of entanglement if the animal is carrying fishing gear. In this study, we performed computational fluid dynamics analysis of a 10 m (length over all) right whale to obtain baseline measurements of drag on the animal. Swimming speeds covering known right whale speed range (0.125 m/s to 8 m/s) were tested. We found a weak dependence between drag coefficient and Reynolds number. At a swimming speed of 2 m/s, we analyzed the boundary layer thicknesses, the flow regimes, and drag components. We found the thickest boundary layer at the lateral sides of the peduncle, whereas the boundary layer thickness over the outer part of the flukes was less than 1.7 cm. Laminar flow occurred over the anterior ~0.6 LoA and turbulent flow from ~0.8 LoA to the fluke notch. On the surfaces of the flukes outside of the body wake region, flow was laminar. Our most significant finding is that the drag coefficient (0.0071–0.0059) of a right whale for swimming speeds ranging from 0.25 m/s to 2 m/s is approximately twice that of many previous estimates for cetaceans.

中文翻译：

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由滑翔的北大西洋露脊鲸 (Eubalaena glacialis) 产生的流动状态和水动力的计算流体动力学

需要准确估计对海洋动物的阻力，以研究机车成本、推进效率以及动物携带渔具时缠结的影响。在这项研究中，我们对一头 10 m（总长度）的露脊鲸进行了计算流体动力学分析，以获得对动物阻力的基线测量。测试了覆盖已知露脊鲸速度范围（0.125 m/s 至 8 m/s）的游泳速度。我们发现阻力系数和雷诺数之间存在弱相关性。在 2 m/s 的游泳速度下，我们分析了边界层厚度、流态和阻力分量。我们在花梗的侧面发现了最厚的边界层，而吸虫外部的边界层厚度小于 1.7 厘米。层流发生在前~0。6 LoA 和湍流从 ~0.8 LoA 到侥幸缺口。在身体尾流区域之外的吸尾表面上，流动是层流的。我们最重要的发现是，当游泳速度在 0.25 m/s 到 2 m/s 之间时，露脊鲸的阻力系数 (0.0071–0.0059) 大约是之前许多鲸类动物估计值的两倍。