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Effect of chordwise deformation on propulsive performance of flapping wings in forward flight.

Authors :
Lin, T.
Xia, W.
Hu, S.
Source :
Aeronautical Journal; Feb2021, Vol. 125 Issue 1284, p430-451, 22p
Publication Year :
2021

Abstract

Lack of flexibility limits the performance enhancement of man-made flapping wing Micro Air Vehicles (MAVs). Active chordwise deformation (bending) is introduced into the flapping wing model at low Reynolds number of Re = 200 in the present study. The lattice Boltzmann method with immersed boundary is adopted in the numerical simulation. The effects of the bending amplitude, bending frequency and phase lag between bending and flapping on the propulsive performance are analysed. The numerical results show that all the chordwise deformation parameters including the bending amplitude, bending frequency and phase lag have a great influence on the flow field, Leading-Edge Vortex (LEV), Trailing-Edge Vortex (TEV) and previous Leading-Edge Vortex (pLEV) of the deformable flapping wing, which leads to the variation of the propulsive performance. With decreasing bending amplitude and increasing bending frequency, both the thrust and energy dissipation coefficients increase. The highest thrust coefficient and highest energy dissipation coefficient occur at a phase lag of 180°. On the other hand, strong dependence of the propulsive efficiency on the vortex tangle is found. The highest propulsive efficiency is obtained for the present model at a dimensionless bending amplitude of 0.2, bending frequency of 0.7Hz, and phase lag of 0°. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00019240
Volume :
125
Issue :
1284
Database :
Supplemental Index
Journal :
Aeronautical Journal
Publication Type :
Academic Journal
Accession number :
148002026
Full Text :
https://doi.org/10.1017/aer.2020.72