Numerical Study of stall delay on humpback whale flippers
Numerical Study of stall delay on humpback whale flippers
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DOI：
10.2514/6.2008-584
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发表时间：
2008-01
期刊：
影响因子：
--
通讯作者：
H. Pedro;M. Kobayashi
中科院分区：
文献类型：
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作者：
H. Pedro;M. Kobayashi
这个 Re 值范围是必要的。最近有报道 2 座头鲸鳍状肢经过优化，可防止失速并提高空气动力性能。这些特征使这些动物具有极高的机动性和强大的转弯能力，这是捕捉猎物所必需的。这一观察结果以及座头鲸的雷诺数落在上述低 Re 范围内的事实推动了座头鲸鳍状肢的实验研究。该物种的鳍状肢具有非常典型的扇形前缘，而其他不易操作的物种的鳍状肢则更加光滑。 3 实验将带有结节的鳍和光滑的鳍进行了比较。研究人员报告称，空气动力学性能得到了改善，并且鳍状肢失速的迎角也有所增加。然而，没有进行流动可视化，因此扇形鳍状肢表现更好的原因还没有被揭示。在这项工作中，我们对用于实验研究的装置进行了数值模拟。准确地确定了扇形鳍板和光滑鳍板的非稳态湍流流场，这产生了充分理解所报告的改进背后的机制所必需的详细信息。我们这项工作的目标是增加对这些较低 Re 数流的了解，这将有助于设计更高效的无人机机翼。
this range of Re numbers is necessary. Recently was reported 2 that the humpback whale flipper is optimized to prevent stall and to improve aerodynamic performance. These features allow these animals to be extremely mobile with great turning ability which is necessary to catch prey. This observation together with the fact that the Reynolds number for the humpback whale falls in the aforementioned low Re range propelled the experimental study the humpback whale flipper. The flippers for this species display a very characteristic scalloped leading edge, whereas the flippers of other species less maneuverable are much smoother. 3 The experiments compared a flipper with tubercles with a smooth flipper. The researchers reported an improvement in the aerodynamic performance as well an increase in the angle of attack at which the flipper stalls. However no flow visualization was performed, therefore the reasons why the scalloped flipper performs better were not uncovered. In this work we performed the numerical simulation of the setup used for the experimental study. The unsteady turbulent flow field for the scalloped flipper and for the smooth flipper was accurately determined which produced detailed information necessary to fully understand the mechanism behind the reported improvement. Our goal with this work is to increase the knowledge about these lower Re number flows which will be useful for the design of more ecient UAV’s wings.