Birds and bats frequently reconfigure their wing planform through a combination of flapping and local sweep morphing, suggesting a possible approach for improving the performance of micro aerial vehicles. We explore the effects of combined flapping and local sweep morphing on aerodynamic performance by employing a bio-inspired two-jointed flapping wing with local sweep morphing. The bio-inspired wing consists of inner and outer sections, which flap around the root joint (shoulder) and the midspan joint (wrist), respectively. The aerodynamic forces and the unsteady vortex structures are evaluated by numerically solving the incompressible Navier–Stokes equations. The results show that combined flapping and local sweep morphing can significantly enhance the aerodynamic performance. In particular, the average lift coefficient is 1.50 times greater than that of simple gliding with single local sweep morphing. Combined flapping and local sweep morphing also have a relatively high pitch moment and shift the aerodynamic center position backward, producing advantages in terms of maneuverability/agility and stability. We find that the vortex structures associated with the combined motion feature midspan vortices, which arise from the leading-edge vortices of the inner wing and contribute to the enhanced aerodynamic performance. We show that the kinematics of combined flapping and local sweep morphing can be further optimized if the midspan vortices are captured by the outer wing.

1.
D.
Li
,
S.
Zhao
,
A.
Da Ronch
,
J.
Xiang
,
J.
Drofelnik
,
Y.
Li
,
L.
Zhang
,
Y.
Wu
,
M.
Kintscher
,
H. P.
Monner
 et al, “
A review of modelling and analysis of morphing wings
,”
Prog. Aerosp. Sci.
100
,
46
62
(
2018
).
2.
R. M.
Ajaj
,
C. S.
Beaverstock
, and
M. I.
Friswell
, “
Morphing aircraft: The need for a new design philosophy
,”
Aerosp. Sci. Technol.
49
,
154
166
(
2016
).
3.
M.
Hassanalian
,
A.
Quintana
, and
A.
Abdelkefi
, “
Morphing and growing micro unmanned air vehicle: Sizing process and stability
,”
Aerosp. Sci. Technol.
78
,
130
146
(
2018
).
4.
L.
Chu
,
Q.
Li
,
F.
Gu
,
X.
Du
,
Y.
He
, and
Y.
Deng
, “
Design, modeling, and control of morphing aircraft: A review
,”
Chin. J. Aeronaut.
35
,
220
–246 (
2022
).
5.
A.
Sofla
,
S.
Meguid
,
K.
Tan
, and
W.
Yeo
, “
Shape morphing of aircraft wing: Status and challenges
,”
Mater. Des.
31
,
1284
1292
(
2010
).
6.
J. D.
Eldredge
and
A. R.
Jones
, “
Leading-edge vortices: Mechanics and modeling
,”
Annu. Rev. Fluid Mech.
51
,
75
104
(
2019
).
7.
W.
Shyy
and
H.
Liu
, “
Flapping wings and aerodynamic lift: The role of leading-edge vortices
,”
AIAA J.
45
,
2817
2819
(
2007
).
8.
K.
Taira
and
T.
Colonius
, “
Three-dimensional flows around low-aspect-ratio flat-plate wings at low Reynolds numbers
,”
J. Fluid Mech.
623
,
187
207
(
2009
).
9.
H.
Ben-Gida
,
R.
Gurka
, and
D.
Weihs
, “
Leading-edge vortex as a high-lift mechanism for large-aspect-ratio wings
,”
AIAA J.
58
,
2806
2819
(
2020
).
10.
X. G.
Meng
and
M.
Sun
, “
Aerodynamics and vortical structures in hovering fruit flies
,”
Phys. Fluids
27
,
031901
(
2015
).
11.
C.
Hefler
,
R.
Noda
,
H.
Qiu
, and
W.
Shyy
, “
Aerodynamic performance of a free-flying dragonfly—A span-resolved investigation
,”
Phys. Fluids
32
,
041903
(
2020
).
12.
L.
Wang
,
L.-H.
Feng
,
Y.
Liang
,
Y.-L.
Chen
, and
Z.-Y.
Li
, “
Vortex control strategy for unsteady aerodynamic optimization of a plunging airfoil at a low Reynolds number
,”
Phys. Fluids
33
,
117110
(
2021
).
13.
D.
Zhang
,
Q.-G.
Huang
,
G.
Pan
,
L.-M.
Yang
, and
W.-X.
Huang
, “
Vortex dynamics and hydrodynamic performance enhancement mechanism in batoid fish oscillatory swimming
,”
J. Fluid Mech.
930
,
A28
(
2022
).
14.
W.
Thielicke
and
E. J.
Stamhuis
, “
The influence of wing morphology on the three-dimensional flow patterns of a flapping wing at bird scale
,”
J. Fluid Mech.
768
,
240
260
(
2015
).
15.
D.
Ma
,
Y.
Zhao
,
Y.
Qiao
, and
G.
Li
, “
Effects of relative thickness on aerodynamic characteristics of airfoil at a low Reynolds number
,”
Chin. J. Aeronaut.
28
,
1003
1015
(
2015
).
16.
W.
Shyy
,
Y.
Lian
,
J.
Tang
,
D.
Viieru
, and
H.
Liu
,
Aerodynamics of Low Reynolds Number Flyers
(
Cambridge University Press
,
2008
).
17.
G.-Y.
He
,
S.-G.
Zhang
, and
X.
Zhang
, “
Thrust generation and wake structure of wiggling hydrofoil
,”
Appl. Mathematics Mech.
31
,
585
592
(
2010
).
18.
H.
Wan
,
H.
Dong
, and
G. P.
Huang
, “
Hovering hinge-connected flapping plate with passive deflection
,”
AIAA J.
50
,
2020
2027
(
2012
).
19.
X.
Lin
,
J.
Wu
, and
T.
Zhang
, “
Effect of torsional spring and shape on the performance of bioinspired caudal fin
,”
Phys. Fluids
33
,
071903
(
2021
).
20.
J. A.
Cheney
,
J. P.
Stevenson
,
N. E.
Durston
,
M.
Maeda
,
J.
Song
,
D. A.
Megson-Smith
,
S. P.
Windsor
,
J. R.
Usherwood
, and
R. J.
Bomphrey
, “
Raptor wing morphing with flight speed
,”
J. R. Soc. Interface
18
,
20210349
(
2021
).
21.
A.
Menshchikov
and
A.
Somov
, “
Morphing wing with compliant aileron and slat for unmanned aerial vehicles
,”
Phys. Fluids
31
,
037105
(
2019
).
22.
X.
Su
,
Z.
Yin
,
Y.
Cao
, and
Y.
Zhao
, “
Numerical investigations on aerodynamic forces of deformable foils in hovering motions
,”
Phys. Fluids
29
,
041902
(
2017
).
23.
S.
Wang
,
X.
Zhang
,
G.
He
, and
T.
Liu
, “
Lift enhancement by dynamically changing wingspan in forward flapping flight
,”
Phys. Fluids
26
,
061903
(
2014
).
24.
S.
Wang
,
G.
He
, and
X.
Zhang
, “
Lift enhancement on spanwise oscillating flat-plates in low-Reynolds-number flows
,”
Phys. Fluids
27
,
061901
(
2015
).
25.
C.
Wang
,
Z.
Xu
,
X.
Zhang
, and
S.
Wang
, “
Optimal reduced frequency for the power efficiency of a flat plate gliding with spanwise oscillations
,”
Phys. Fluids
33
,
111908
(
2021
).
26.
K.
Joshi
,
C. G.
Vazquez
,
J. L.
Kauffman
, and
S.
Bhattacharya
, “
Unsteady maneuvering of a morphing wing
,” in
AIAA Scitech 2020 Forum
(AIAA,
2020
), p.
0333
.
27.
K.
Jia
,
T.
Scofield
,
M.
Wei
, and
S.
Bhattacharya
, “
Vorticity transfer in a leading-edge vortex due to controlled spanwise bending
,”
Phys. Rev. Fluids
6
,
024703
(
2021
).
28.
B.
Parslew
, “
Predicting power-optimal kinematics of avian wings
,”
J. R. Soc. Interface
12
,
20140953
(
2015
).
29.
D.
Lentink
,
U.
Müller
,
E.
Stamhuis
,
R.
de Kat
,
W.
van Gestel
,
L.
Veldhuis
,
P.
Henningsson
,
A.
Hedenström
,
J. J.
Videler
, and
J. L.
van Leeuwen
, “
How swifts control their glide performance with morphing wings
,”
Nature
446
,
1082
1085
(
2007
).
30.
P.
Henningsson
,
L. C.
Johansson
, and
A.
Hedenström
, “
How swift are swifts Apus apus?
,”
J. Avian Biol.
41
,
94
98
(
2010
).
31.
K.
Zhang
,
S.
Hayostek
,
M.
Amitay
,
A.
Burtsev
,
V.
Theofilis
, and
K.
Taira
, “
Laminar separated flows over finite-aspect-ratio swept wings
,”
J. Fluid Mech.
905
,
R1
(
2020
).
32.
K.
Zhang
and
K.
Taira
, “
Laminar vortex dynamics around forward-swept wings
,”
Phys. Rev. Fluids
7
,
024704
(
2022
).
33.
R.
Zangeneh
, “
Investigating sweep effects on the stability of leading-edge vortices over finite-aspect ratio pitch-up wings
,”
Phys. Fluids
33
,
107104
(
2021
).
34.
D. D.
Chin
,
L. Y.
Matloff
,
A. K.
Stowers
,
E. R.
Tucci
, and
D.
Lentink
, “
Inspiration for wing design: How forelimb specialization enables active flight in modern vertebrates
,”
J. R. Soc. Interface
14
,
20170240
(
2017
).
35.
E.
Chang
,
L. Y.
Matloff
,
A. K.
Stowers
, and
D.
Lentink
, “
Soft biohybrid morphing wings with feathers underactuated by wrist and finger motion
,”
Sci. Rob.
5
,
eaay1246
(
2020
).
36.
T.
Wolf
and
R.
Konrath
, “
Avian wing geometry and kinematics of a free-flying barn owl in flapping flight
,”
Exp. Fluids
56
,
1
16
(
2015
).
37.
A. K.
Stowers
,
L. Y.
Matloff
, and
D.
Lentink
, “
How pigeons couple three-dimensional elbow and wrist motion to morph their wings
,”
J. R. Soc. Interface
14
,
20170224
(
2017
).
38.
T.
Liu
,
K.
Kuykendoll
,
R.
Rhew
, and
S.
Jones
, “
Avian wing geometry and kinematics
,”
AIAA J.
44
,
954
963
(
2006
).
39.
J.-S.
Maeng
,
J.-H.
Park
,
S.-M.
Jang
, and
S.-Y.
Han
, “
A modeling approach to energy savings of flying Canada geese using computational fluid dynamics
,”
J. Theor. Biol.
320
,
76
85
(
2013
).
40.
S.
Qin
,
Z.
Weng
,
Z.
Li
,
Y.
Xiang
, and
H.
Liu
, “
On the controlled evolution for wingtip vortices of a flapping wing model at bird scale
,”
Aerosp. Sci. Technol.
110
,
106460
(
2021
).
41.
X.
Lang
,
B.
Song
,
W.
Yang
, and
X.
Yang
, “
Effect of spanwise folding on the aerodynamic performance of three dimensional flapping flat wing
,”
Phys. Fluids
34
,
021906
(
2022
).
42.
Z.
Hui
,
Y.
Zhang
, and
G.
Chen
, “
Aerodynamic performance investigation on a morphing unmanned aerial vehicle with bio-inspired discrete wing structures
,”
Aerosp. Sci. Technol.
95
,
105419
(
2019
).
43.
E.
Ajanic
,
M.
Feroskhan
,
S.
Mintchev
,
F.
Noca
, and
D.
Floreano
, “
Bioinspired wing and tail morphing extends drone flight capabilities
,”
Sci. Rob.
5
,
eabc2897
(
2020
).
44.
A. E.
Pete
,
D.
Kress
,
M. A.
Dimitrov
, and
D.
Lentink
, “
The role of passive avian head stabilization in flapping flight
,”
J. R. Soc. Interface
12
,
20150508
(
2015
).
45.
K.
Suzuki
,
I.
Okada
, and
M.
Yoshino
, “
Effect of wing mass on the free flight of a butterfly-like model using immersed boundary–lattice Boltzmann simulations
,”
J. Fluid Mech.
877
,
614
647
(
2019
).
46.
R.
Xu
,
X.
Zhang
, and
H.
Liu
, “
Effects of wing-to-body mass ratio on insect flapping flights
,”
Phys. Fluids
33
,
021902
(
2021
).
47.
G. K.
Taylor
,
R. L.
Nudds
, and
A. L.
Thomas
, “
Flying and swimming animals cruise at a Strouhal number tuned for high power efficiency
,”
Nature
425
,
707
711
(
2003
).
48.
S.
Wang
and
X.
Zhang
, “
An immersed boundary method based on discrete stream function formulation for two-and three-dimensional incompressible flows
,”
J. Comput. Phys.
230
,
3479
3499
(
2011
).
49.
S.
Wang
,
G.
He
, and
X.
Zhang
, “
Parallel computing strategy for a flow solver based on immersed boundary method and discrete stream-function formulation
,”
Comput. Fluids
88
,
210
224
(
2013
).
50.
W.
Shyy
,
P.
Trizila
,
C.-K.
Kang
, and
H.
Aono
, “
Can tip vortices enhance lift of a flapping wing?
,”
AIAA J.
47
,
289
293
(
2009
).
51.
F. T.
Muijres
,
P.
Henningsson
,
M.
Stuiver
, and
A.
Hedenström
, “
Aerodynamic flight performance in flap-gliding birds and bats
,”
J. Theor. Biol.
306
,
120
128
(
2012
).
52.
H.
Liu
,
T.
Nakata
,
N.
Gao
,
M.
Maeda
,
H.
Aono
, and
W.
Shyy
, “
Micro air vehicle-motivated computational biomechanics in bio-flights: Aerodynamics, flight dynamics and maneuvering stability
,”
Acta Mech. Sin.
26
,
863
879
(
2010
).
53.
H.
Zheng
,
F.
Xie
,
T.
Ji
, and
Y.
Zheng
, “
Kinematic parameter optimization of a flapping ellipsoid wing based on the data-informed self-adaptive quasi-steady model
,”
Phys. Fluids
32
,
041904
(
2020
).
54.
T. de P.
Vasconcelos
,
D. A.
de Souza
,
C. L.
Mattos
, and
J. P.
Gomes
, “
No-PASt-BO: Normalized portfolio allocation strategy for Bayesian optimization
,” in
2019 IEEE 31st International Conference on Tools with Artificial Intelligence (ICTAI)
(
IEEE
,
2019
), pp.
561
568
.
55.
C.
Wang
,
Z.
Xu
,
X.
Zhang
, and
S.
Wang
, “
Bayesian optimization for the spanwise oscillation of a gliding flat-plate
,” arXiv:2109.04382 (
2021
).
56.
R.
Yondo
,
E.
Andrés
, and
E.
Valero
, “
A review on design of experiments and surrogate models in aircraft real-time and many-query aerodynamic analyses
,”
Prog. Aerosp. Sci.
96
,
23
61
(
2018
).
57.
A. L.
Marsden
,
M.
Wang
,
J. E.
Dennis
, and
P.
Moin
, “
Optimal aeroacoustic shape design using the surrogate management framework
,”
Optim. Eng.
5
,
235
262
(
2004
).
58.
B. W.
Tobalske
and
K. P.
Dial
, “
Flight kinematics of black-billed magpies and pigeons over a wide range of speeds
,”
J. Exp. Biol.
199
,
263
280
(
1996
).
59.
B. W.
Tobalske
,
W. L.
Peacock
, and
K. P.
Dial
, “
Kinematics of flap-bounding flight in the zebra finch over a wide range of speeds
,”
J. Exp. Biol.
202
,
1725
1739
(
1999
).
60.
M.
Wolf
,
L. C.
Johansson
,
R.
von Busse
,
Y.
Winter
, and
A.
Hedenström
, “
Kinematics of flight and the relationship to the vortex wake of a Pallas' long tongued bat (Glossophaga soricina
),”
J. Exp. Biol.
213
,
2142
2153
(
2010
).
61.
K.
Zhang
,
S.
Hayostek
,
M.
Amitay
,
W.
He
,
V.
Theofilis
, and
K.
Taira
, “
On the formation of three-dimensional separated flows over wings under tip effects
,”
J. Fluid Mech.
895
,
A9
(
2020
).
62.
P.
Lissaman
, “
Low-Reynolds-number airfoils
,”
Annu. Rev. Fluid Mech.
15
,
223
239
(
1983
).
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