Optimal pitching axis of flapping-wings for hovering flight

2014 ◽  
pp. 409-414
Author(s):  
Q Wang ◽  
J Goosen ◽  
F van Keulen
Keyword(s):  
Flapping Wings ◽  
Hovering Flight

Aerodynamic effects of deviating motion of flapping wings in hovering flight

2019 ◽  
Vol 14 (2) ◽  
pp. 026006 ◽  
Author(s):  
Ho-Young Kim ◽  
Jong-Seob Han ◽  
Jae-Hung Han
Keyword(s):  
Flapping Wings ◽  
Hovering Flight

scholarly journals Stable hovering of a jellyfish-like flying machine

2014 ◽  
Vol 11 (92) ◽  
pp. 20130992 ◽  
Author(s):  
Leif Ristroph ◽  
Stephen Childress
Keyword(s):  
High Speed ◽  
Motion Tracking ◽  
The Body ◽  
Flapping Wings ◽  
Wing Size ◽  
Centre Of Mass ◽  
Hovering Flight ◽  
High Speed Video ◽  
Aerodynamic Model ◽  
Aerodynamic Surfaces

Ornithopters, or flapping-wing aircraft, offer an alternative to helicopters in achieving manoeuvrability at small scales, although stabilizing such aerial vehicles remains a key challenge. Here, we present a hovering machine that achieves self-righting flight using flapping wings alone, without relying on additional aerodynamic surfaces and without feedback control. We design, construct and test-fly a prototype that opens and closes four wings, resembling the motions of swimming jellyfish more so than any insect or bird. Measurements of lift show the benefits of wing flexing and the importance of selecting a wing size appropriate to the motor. Furthermore, we use high-speed video and motion tracking to show that the body orientation is stable during ascending, forward and hovering flight modes. Our experimental measurements are used to inform an aerodynamic model of stability that reveals the importance of centre-of-mass location and the coupling of body translation and rotation. These results show the promise of flapping-flight strategies beyond those that directly mimic the wing motions of flying animals.

scholarly journals Optimal pitching axis location of flapping wings for efficient hovering flight

2017 ◽  
Vol 12 (5) ◽  
pp. 056001 ◽  
Author(s):  
Q Wang ◽  
J F L Goosen ◽  
F van Keulen
Keyword(s):  
Flapping Wings ◽  
Hovering Flight

Passive Pitching Mechanism of Three-Dimensional Flapping Wings in Hovering Flight

2019 ◽  
Author(s):  
Chengyu Li ◽  
Junshi Wang ◽  
Geng Liu ◽  
Xiaolong Deng ◽  
Haibo Dong
Keyword(s):  
Computational Study ◽  
Fluid Dynamic ◽  
Flapping Wings ◽  
Clear Understanding ◽  
Basal Region ◽  
Mass Ratio ◽  
Hovering Flight ◽  
Pitching Motion ◽  
Wide Range ◽  
Cauchy Number

Abstract Flapping wings of insects can passively maintain a high angle of attack due to the torsional flexibility of wing basal region without the aid of the active pitching motion. However, the lift force generated by such passive pitching motion has not been well explored in the literature. Consequently, there is no clear understanding of how torsional wing flexibility should be designed for optimal performance. In this work, a computational study was conducted to investigate the passive pitching mechanism of flapping wings in hovering flight using a torsional spring model. The torsional wing flexibility was characterized by Cauchy number. The impacts of the inertial effect of wings were evaluated using the mass ratio. The aerodynamic forces and associated unsteady flow structures were simulated by an in-house immersed-boundary-method based computational fluid dynamic solver. A parametric study on the Cauchy number was performed with a Reynolds number of 300 at a mass ratio of 1.0, which covers a wide range of species of insect wings. According to the analysis of the aerodynamic performance, we found that the optimal lift can be achieved at a Cauchy number around 0.16, while the optimal efficiency in terms of lift-to-power ratio was reached at a Cauchy number around 0.3. All the corresponding wing pitching kinematics had a pitching magnitude around 60 degrees with slightly advanced rotation. In addition, 3D wake structures generated by the passive flapping wings were analyzed in detail. The findings of this work could provide important implications for designing more efficient flapping-wing micro air vehicles.

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