Open AccessEnergy extraction properties of a flapping wing with a deformable airfoil
Author(s) -
Zhu Bing,
Zhang Wei,
Huang Yun
Publication year - 2019
Publication title -
iet renewable power generation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.005
H-Index - 76
ISSN - 1752-1424
DOI - 10.1049/iet-rpg.2018.6193
Subject(s) - airfoil , wing , trailing edge , leading edge , flapping , camber (aerodynamics) , mechanics , foil method , vortex , curvature , angle of attack , acoustics , physics , aerodynamics , materials science , structural engineering , engineering , geometry , mathematics , composite material
Flapping wing devices have attracted considerable attention as a new means of power extraction. The present study applies transient numerical calculations based on the dynamic mesh technique to investigate the influences of leading edge, trailing edge, or overall circular arc airfoil deformations on the power extraction efficiencies of a flapping wing device under the condition of maintaining a constant arc length along the mean camber line of the foil. The results indicate that airfoil deformations can improve the power extraction efficiency of the flapping wing device. The primary reason is that the active synchronised deformation of the foil increases the effective curvature and the velocity circulation around the foil. In addition, the performance curve of the flapping wing device exhibits two frequency ranges with relative high efficiency. In the low frequency region, if the leading edge vortex (LEV) detaches from the trailing edge just as the foil reverses its heaving direction, the foil will gain much more energy due to the positive power extraction of the pitching moment. In the high frequency region, a small steady body‐attached vortex (BAV) maintains a high lift, and, thus, the device extracts more power due to the enhanced heaving force.