Leakage of an eagle flight feather and its influence on the aerodynamics
Di Tang (唐迪)1,2,†, Dawei Liu(刘大伟)2,‡, Yin Yang(杨茵)2, Yang Li(李阳)2, Xipeng Huang(黄喜鹏)1, and Kai Liu(刘凯)3
1 College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310014, China; 2 High Speed Aerodynamic Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China; 3 Chengdu State-Owned Jinjiang Machine Factory, Chendu 610043, China
Abstract We investigate how the barb of bird feathers is changed along both the rachis and barb. To investigate the microstructures and the mechanical behaviors of barbs, a series of barbs are manually cut from an eagle's primary feather to observe the cross sections. A Λ -like cross section with a tiny hook is observed at the right feet at each section. Afterwards, a measurement of the setup system is developed to evaluate the leakage ratio of a feather followed by a numerical predicting approach based on the CFD method. It is found that the air leakage increases linearly against the pressure, and the predicted results coincide well with the experimental results. Finally, the influences of leakage of the flight feather on both steady and unsteady aerodynamics are studied.
Fund: Project supported by the National Natural Science Foundation of China (Grant No. 51705459) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LY20E050022).
Di Tang (唐迪), Dawei Liu(刘大伟), Yin Yang(杨茵), Yang Li(李阳), Xipeng Huang(黄喜鹏), and Kai Liu(刘凯) Leakage of an eagle flight feather and its influence on the aerodynamics 2021 Chin. Phys. B 30 034701
Altmetric calculates a score based on the online attention an article receives. Each coloured thread in the circle represents a different type of online attention. The number in the centre is the Altmetric score. Social media and mainstream news media are the main sources that calculate the score. Reference managers such as Mendeley are also tracked but do not contribute to the score. Older articles often score higher because they have had more time to get noticed. To account for this, Altmetric has included the context data for other articles of a similar age.