Many species of owls are able to fly noiselessly, and their wing feathers play an important role for the silent flight. In this paper, we studied the sound suppression mechanism of the eagle owl （Bubo bubo） by Stere...Many species of owls are able to fly noiselessly, and their wing feathers play an important role for the silent flight. In this paper, we studied the sound suppression mechanism of the eagle owl （Bubo bubo） by Stereo Microscope （SM）, Scanning Electron Microscopy （SEM） and Laser Scanning Confocal Microscope （LSCM）. To investigate the effects of special charac- teristics of wing feather on owl silent flight, the acoustic properties, including the sound absorption coefficient and flight noise, were compared between the eagle owl and common buzzard （Buteo buteo）. The results show that the eagle owl generates lower noise than common buzzard during flight, and its wing feather has better sound absorption properties. The leading edge serration and trailing edge fringe can improve the pressure fluctuation of turbulence boundary, and suppress the generation of vortex sound. The elongated distal barbules form a multi-layer grid porous structure which also has an effect on sound absorption. This research not only can give the inspiration for solving the aerodynamic noise of aircraft and engineering machine, but also can provide a new idea for the design of low-noise devices.展开更多
基金Acknowledgments This work is supported by the Special Funds of National Natural Science Foundation of China （Grant No. 31071928）, the International Cooperation Project of National Natural Science Foundation of China （Grant No. 50920105504）, the Science Development Foundation of Jilin Province （Grant No. 20090340）, the Basic Research of High-speed Rail Joint Funds of the National Natural Science Foundation of China （Grant No. Ul134109）, and the Specialized Research Fund for the Doctoral Program of Higher Education of China （Grant No. 20110061120048）
文摘Many species of owls are able to fly noiselessly, and their wing feathers play an important role for the silent flight. In this paper, we studied the sound suppression mechanism of the eagle owl （Bubo bubo） by Stereo Microscope （SM）, Scanning Electron Microscopy （SEM） and Laser Scanning Confocal Microscope （LSCM）. To investigate the effects of special charac- teristics of wing feather on owl silent flight, the acoustic properties, including the sound absorption coefficient and flight noise, were compared between the eagle owl and common buzzard （Buteo buteo）. The results show that the eagle owl generates lower noise than common buzzard during flight, and its wing feather has better sound absorption properties. The leading edge serration and trailing edge fringe can improve the pressure fluctuation of turbulence boundary, and suppress the generation of vortex sound. The elongated distal barbules form a multi-layer grid porous structure which also has an effect on sound absorption. This research not only can give the inspiration for solving the aerodynamic noise of aircraft and engineering machine, but also can provide a new idea for the design of low-noise devices.
