Comparison of experimental and numerical studies on the flow structures of hovering hawkmoths
Comparison of experimental and numerical studies on the flow structures of hovering hawkmoths
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DOI：
10.1016/j.jfluidstructs.2021.103405
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发表时间：
2021-10-09
影响因子：
3.6
通讯作者：
Li, Chengyu
中科院分区：
文献类型：
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作者：
Liu, Yun;Lozano, Angel David;Li, Chengyu
本研究旨在比较昆虫悬停尾流结构的实验显示与数值模拟。利用高速纹影摄影系统，在机翼表面刷上异丙醇，对自由悬停的天蛾尾流进行了可视化和捕捉。同时，基于浸没边界法（IBM）的计算流体动力学（CFD）模拟进行了悬停天蛾的整个流场的解决。在悬停的天蛾的每一个机翼上，纹影摄影实验和CFD模拟都捕获并可视化了非常相似的尾流结构，包括下冲程中的涡环结构和上冲程中的梢/根涡。此外，通过测量涡结构的尺寸，将实验结果与模拟结果进行了比较。实验与仿真结果在流场结构形成及其大小上的一致性表明，所实现的基于IBM的CFD仿真方法能够以有效的流场结构细节（如流场结构大小）来模拟悬停昆虫上的实际流场现象。另一方面，我们的研究证实了高速纹影摄影捕捉尾流结构形成的能力，这是具有挑战性的解决与其他方法。(c)2021由Elsevier Ltd.出版
This study presents an effort on comparing the wake flow structures of hovering insects between experimental visualization and computational simulation. The wake flow on a freely hovering hawkmoth was visualized and captured, utilizing a high-speed schlieren photography system with isopropyl alcohol brushed on the wing surfaces. Meanwhile, an Immersed Boundary Method (IBM) based computational fluid dynamics (CFD) simulation was carried out on a hovering hawkmoth to resolve the entire flow field. On each wing of the hovering hawkmoths, both the schlieren photography experiment and the CFD simulation captured and visualized very alike wake structures, consisting of a vortex loop structure in the down-stroke and tip/root vortices in the up-stroke. Furthermore, the experiment and simulation results are compared by measuring the sizes of the vortex structures. The agreement in flow structure formation and its size between the experiment and simulation suggests that the implemented IBM-based CFD simulation method is capable of simulating the actual flow phenomena on the hovering insect with valid flow structure details such as flow structure size. On the other hand, our study confirms the high-speed schlieren photography's capability of capturing the wake flow structures formation, which is challenging to resolve with other methods. (c) 2021 Published by Elsevier Ltd.