Aerodynamic interactions between wing and body of a model insect in forward flight and maneuvers

Liang, Bin; Sun, Mao

doi:10.1016/s1672-6529(13)60195-x

Cited by 27 publications

(27 citation statements)

References 22 publications

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“…In general, the vortical structures including the LEVs and the tip vortices around the wings are identical in both cases. This is consistent with those found in the previous studies of insect forward flight(Yu & Sun 2009;Liang & Sun 2013). However, there are two unique sets of vortical structures generated by the cicada body, the thorax vortex (TXV) and the posterior body vortex (Colour online) A series of instantaneous wake structures, visualized by λ = 2.5, during upstroke for WB model (a-c) and WN model(d-f ): (a,d) t/T = 0.74; (b,e) t/T = 0.9; (c,f ) t/T = 0.98.…”

supporting

confidence: 93%

“…The average lift enhancement on wings due to the WBI is about 6.7 %. This is slightly higher than that found in previous studies (Aono et al 2008;Yu & Sun 2009;Liang & Sun 2013), which is due to the stronger WBI.…”

Section: Aerodynamic Performancecontrasting

confidence: 75%

“…The lift coefficient increases by nearly 18.7 % at the lower end of the minimum distance range. Such a behaviour has a particular relevance for the studies of the fruit fly model (Liang & Sun 2013), in which the δ is about 0.25c and the relative lift increase is about 7.2 %. Figure 14 presents perspective views of the vortex topology and the spanwise vorticity slices for δ = 0.2c and this can be examined in conjunction with the corresponding plot for δ = 0.07c (figures 6b and 9a).…”

Section: Surface Pressurementioning

confidence: 91%

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Vortex dynamics and new lift enhancement mechanism of wing–body interaction in insect forward flight

Dong

2016

J. Fluid Mech.

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The effects of wing-body interaction (WBI) on aerodynamic performance and vortex dynamics have been numerically investigated in the forward flight of cicadas. Flapping wing kinematics was reconstructed based on the output of a high-speed camera system. Following the reconstruction of cicada flight, three models, wing-body (WB), body-only (BD) and wings-only (WN), were then developed and evaluated using an immersed-boundary-method-based incompressible Navier-Stokes equations solver. Results have shown that due to WBIs, the WB model had a 18.7 % increase in total lift production compared with the lift generated in both the BD and WN models, and about 65 % of this enhancement was attributed to the body. This resulted from a dramatic improvement of body lift production from 2 % to 11.6 % of the total lift produced by the wing-body system. Further analysis of the associated near-field and far-field vortex structures has shown that this lift enhancement was attributed to the formation of two distinct vortices shed from the thorax and the posterior of the insect, respectively, and their interactions with the flapping wings. Simulations are also used to examine the new lift enhancement mechanism over a range of minimum wing-body distances, reduced frequencies and body inclination angles. This work provides a new physical insight into the understanding of the body-involved lift-enhancement mechanism in insect forward flight.

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supporting

confidence: 93%

Section: Aerodynamic Performancecontrasting

confidence: 75%

Section: Surface Pressurementioning

confidence: 91%

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Vortex dynamics and new lift enhancement mechanism of wing–body interaction in insect forward flight

Dong

2016

J. Fluid Mech.

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“…But at hovering, the aerodynamic force of the body is negligibly small compared to that of the wings because the body does not move. Furthermore, it has been shown that the wings and the body do not interact aerodynamically, neither do the contralateral wings (Aono et al 2008;Yu & Sun 2009;Liang & Sun 2013). Therefore, in the present study, only one wing is simulated.…”

Section: A2 Flow Solution Methods and Grid Testsmentioning

confidence: 98%

Aerodynamic-force production mechanisms in hovering mosquitoes

Liu

Sun

2020

J. Fluid Mech.

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“…Furthermore, it has been shown that the wings and the body do not interact aerodynamically, neither do the contralateral wings. [34][35][36] Therefore, in the present study, only one wing is simulated. The model wings are flat plates with rounded leading and trailing edges, and the thickness of the plate is 0.03c.…”

Section: B the Navier-stokes Equations And Solution Methodsmentioning

confidence: 99%

Aerodynamics and vortical structures in hovering fruitflies

Meng

Sun

2015

Physics of Fluids

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We measure the wing kinematics and morphological parameters of seven freely hovering fruitflies and numerically compute the flows of the flapping wings. The computed mean lift approximately equals to the measured weight and the mean horizontal force is approximately zero, validating the computational model. Because of the very small relative velocity of the wing, the mean lift coefficient required to support the weight is rather large, around 1.8, and the Reynolds number of the wing is low, around 100. How such a large lift is produced at such a low Reynolds number is explained by combining the wing motion data, the computed vortical structures, and the theory of vorticity dynamics. It has been shown that two unsteady mechanisms are responsible for the high lift. One is referred as to "fast pitching-up rotation": at the start of an up-or downstroke when the wing has very small speed, it fast pitches down to a small angle of attack, and then, when its speed is higher, it fast pitches up to the angle it normally uses. When the wing pitches up while moving forward, large vorticity is produced and sheds at the trailing edge, and vorticity of opposite sign is produced near the leading edge and on the upper surface, resulting in a large time rate of change of the first moment of vorticity (or fluid impulse), hence a large aerodynamic force. The other is the well known "delayed stall" mechanism: in the mid-portion of the up-or downstroke the wing moves at large angle of attack (about 45 deg) and the leading-edge-vortex (LEV) moves with the wing; thus, the vortex ring, formed by the LEV, the tip vortices, and the starting vortex, expands in size continuously, producing a large time rate of change of fluid impulse or a large aerodynamic force. C 2015 AIP Publishing LLC. [http://dx.dynamic stall vortex (they called it the leading edge vortex, LEV) did not shed in a downstroke or upstroke, even if the wing traveled more than five chord lengths in a downstroke. Their analysis of the momentum imparted to the fluid by the vortex wake showed that the LEV could produce enough lift for weight support. The above studies identified delayed stall (or maintaining the LEV on the wing) as a high-lift mechanism of insects. This was confirmed by subsequent experimental and numerical studies on rotating and flapping wings (e.g., Refs. 6-15). Furthermore, in these studies, 6-15 the development of the LEV was studied in detail and how the LEV attachment was maintained was explained.The wing stroke of an insect is typically divided into four portions: two translations (upstroke translation and downstroke translation) and two rotations around stroke reversal (pronation and supination). 7,16 The above delayed stall mechanism operates during the translational phases. 5,6 Dickinson et al. 7 explored the rotational phases by measuring the aerodynamic forces of a dynamically scaled model fruitfly. On the basis of wing kinematics measured in tethered fruitflies, they assumed the following wing motion pattern: the translational velocity varied accor...

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Aerodynamic interactions between wing and body of a model insect in forward flight and maneuvers

Cited by 27 publications

References 22 publications

Vortex dynamics and new lift enhancement mechanism of wing–body interaction in insect forward flight

Vortex dynamics and new lift enhancement mechanism of wing–body interaction in insect forward flight

Aerodynamic-force production mechanisms in hovering mosquitoes

Aerodynamics and vortical structures in hovering fruitflies

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