Effects of phase lag on the hovering flight of damselfly and dragonfly

Zou, Pei-Yi; Lai, Yu-Hsiang; Yang, Jing‐Tang

doi:10.1103/physreve.100.063102

Cited by 26 publications

(10 citation statements)

References 35 publications

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“…8: 202275 a basis for the subsequent experimental and numerical work, while with further observation of dragonflies, the researchers found that the phase difference in their hovering was not constant. In most cases, dragonflies hovered with γ = 180°; while in a few cases, smaller phase differences between 60°and 90°were applied [9,10]. The wing geometry and kinematics of dragonflies in this study are mainly based on data from Norberg's measurement [27,28].…”

Section: Wing Geometry and Kinematicsmentioning

confidence: 99%

“…The phase difference is an important kinematic parameter for the interaction which is defined as the phase angle by which the HW leads the FW. According to the observations of dragonfly flight [9][10][11][12][13][14][15][16][17] and the studies of phase difference [18][19][20], it was concluded that dragonflies could make various kinds of interactions by adjusting phase difference in different flight conditions, and the change of phase difference had an impact on aerodynamic performance of tandem-wing (TW) flapping. Adjusting phase difference in a TW flapping might be an outstanding method to control flight performance.…”

Section: Introductionmentioning

confidence: 99%

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Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

et al. 2021

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Dragonflies possess two pairs of wings and the interactions between forewing (FW) and hindwing (HW) play an important role in dragonfly flight. The effects of tandem-wing (TW) interactions on the aerodynamic performance of dragonfly hovering have been investigated. Numerical simulations of single-wing hovering without interactions and TW hovering with interactions are conducted and compared. It is found that the TW interactions reduce the lift coefficient of FW and HW by 7.36% and 20.25% and also decrease the aerodynamic power and efficiency. The above effects are mainly caused by the interaction between the vortex structures of the FW and the HW, which makes the pressure of the wing surface and the flow field near the wings change. During the observations of dragonfly flight, it is found that the phase difference ( γ ) is not fixed. To explore the influence of phase difference on aerodynamic performance, TW hovering with different phase differences is studied. The results show that at γ = 22.5°, dragonflies produce the maximum lift which is more than 20% of the body weight with high efficiency; at γ = 180°, dragonflies generate the same lift as the body weight.

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Section: Wing Geometry and Kinematicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

et al. 2021

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“…To analyse the effect of the wing-pitch motion among varied cases ( §4), we assumed the wings to be flat plates to separate the effect of the wing-pitch motion from the wing flexibility. Many authors presented satisfactory results using flat plates [34][35][36][37][38]; the use of a flat plate does not affect the natural trend of flight of a butterfly [5,39]. Table 1 shows a comparison of the geometry and features between the experimental butterflies and the butterfly model.…”

Section: Numerical Model and Simulation Schemementioning

confidence: 99%

Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly

et al. 2021

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Unlike other insects, a butterfly uses a small amplitude of the wing-pitch motion for flight. From an analysis of the dynamics of real flying butterflies, we show that the restrained amplitude of the wing-pitch motion enhances the wake-capture effect so as to enhance forward propulsion. A numerical simulation refined with experimental data shows that, for a small amplitude of the wing-pitch motion, the shed vortex generated in the downstroke induces air in the wake region to flow towards the wings. This condition enables a butterfly to capture an induced flow and to acquire an additional forward propulsion, which accounts for more than 47% of the thrust generation. When the amplitude of the wing-pitch motion exceeds 45°, the flow induced by the shed vortex drifts away from the wings; it attenuates the wake-capture effect and causes the butterfly to lose a part of its forward propulsion. Our results provide one essential aerodynamic feature for a butterfly to adopt a small amplitude of the wing-pitch motion to enhance the wake-capture effect and forward propulsion. This work clarifies the variation of the flow field correlated with the wing-pitch motion, which is useful in the design of wing kinematics of a micro-aerial vehicle.

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“…The local angle of attack can strongly influence the unsteady lift-generating mechanisms of flapping flight (Thomas et al 2004;Bomphrey et al 2016). It was also shown that the synchronized phasing and pitching of the wings in hovering flight can help dragonflies overcome the adverse effects of root vortex interaction with LEV formation (Zou, Lai & Yang 2019). A previous study based on the flight of a living dragonfly using smoke visualization in a wind tunnel shows that the effective angle of attack of the flapping wing played a primary role in the formation, attachment and shedding of the LEV (Thomas et al 2004).…”

Section: Introductionmentioning

confidence: 99%

The interplay of kinematics and aerodynamics in multiple flight modes of a dragonfly

et al. 2023

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This paper presents the effects of wing kinematics on both normal forward flight and escape flight of a dragonfly. A Navier–Stokes-based numerical model has been adopted, and results have been substantiated by experimental data. The wing kinematics of tethered specimens and the prescribed wing morphology of a free-flying dragonfly were used in the simulation. To shed light on the interplay between kinematics and aerodynamics, a parametric study of the kinematics has been conducted. It is found that in escape flight, the dragonfly generates additional lift while the thrust reduces and the overall efficiency drops. Compared with normal forward flight, the escape mode produces larger lift force peaks. When the kinematics change to facilitate escape flight, the aerodynamic forces are affected by not only the flapping kinematics but, in the case of the hindwing, the varied wing–wing vortex interactions. The direction of the resultant force on each wing changes according to the change of the mean of pitching angle and stroke plane angle. We found that in the studied configurations, the varied phasing of the wings has a marginal effect on the aerodynamics of the dragonfly. It reduces lift and increases thrust, and this force modulation is slightly more efficient when the local angle of attack also changes. On the other hand, the change of angle of attack played a major role in leading-edge vortex formations and directing the resultant forces of the wings. The results can be useful in developing flight control strategies for micro air vehicle design.

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Effects of phase lag on the hovering flight of damselfly and dragonfly

Cited by 26 publications

References 35 publications

Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

Beneficial wake-capture effect for forward propulsion with a restrained wing-pitch motion of a butterfly

The interplay of kinematics and aerodynamics in multiple flight modes of a dragonfly

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