Nowadays, wind turbines operate within complex inflow environments. Meanwhile, installing Gurney flaps on existing wind turbines could enhance wind energy efficiency. However, limited research has been conducted on the variation of aerodynamic characteristics of a wind turbine equipped with Gurney flaps under turbulent inflow conditions. Hence, wind tunnel test comparisons were made between the output power, wind load, and wake characteristics of a model wind turbine with and without Gurney flaps. The results demonstrated a correlation between the additional power increase in the wind turbine equipped with Gurney flaps and the aerodynamic variation of the corresponding airfoil. Gurney flaps could be effective at higher tip speed ratios, and the power enhancement efficiency initially increased but then decreased as turbulence intensity increased from a low value to 19.0%. Installing Gurney flaps resulted in significant pulsation peaks within the original inertial sub-range. The time-averaged thrust coefficient shifts upward, but the difference decreases slightly under turbulent conditions. Wake analysis revealed that the presence of additional wake velocity deficits primarily concentrated within the near-wake region, which extends along the spanwise direction. These findings could enhance a better understanding of the aerodynamic performances of wind turbines installing Gurney flaps under varying turbulent flow conditions.

1.
P.
Veers
,
K.
Dykes
,
E.
Lantz
et al, “
Grand challenges in the science of wind energy
,”
Science
366
(
6464
),
eaau2027
(
2019
).
2.
J.
Wang
,
Y.
Li
, and
K.-S.
Choi
, “
Gurney flap-Lift enhancement, mechanisms and applications
,”
Prog. Aerosp. Sci.
44
(
1
),
22
47
(
2008
).
3.
H.
Fatahian
,
H.
Salarian
,
M. E.
Nimvari
et al, “
Effect of Gurney flap on flow separation and aerodynamic performance of an airfoil under rain and icing conditions
,”
Acta Mech. Sin.
36
(
3
),
659
677
(
2020
).
4.
C. X.
Li
,
C.
Zhang
,
R. X.
Zhang
et al, “
Effect of Gurney flap on performance and aeroacoustics of variable-pitch axial fans
,”
AIAA J.
58
(
6
),
2546
2559
(
2020
).
5.
M.
Masdari
,
M.
Mousavi
, and
M.
Tahani
, “
Dynamic stall of an airfoil with different mounting angle of gurney flap
,”
Aircr. Eng.
92
(
7
),
1037
1048
(
2020
).
6.
Y.
Li
,
H. P.
Wang
, and
Z. G.
Wu
, “
Aerodynamic characteristic of wind turbine with the leading edge slat and microtab
,”
Sustainable Energy Technol. Assess.
52
,
101957
(
2022
).
7.
D.
Arivoli
and
I.
Singh
, “
Effect of Gurney flap on the vortex-dominated flow over low-AR wings
,”
Exp. Fluids
64
(
4
),
68
(
2023
).
8.
Z.
Cui
,
Q.
Xie
,
H.
Zhang
et al, “
Aerodynamic characteristics of Gurney flaps under special atmosphere
,”
Acta Aerodyn. Sin.
37
(
6
),
908
914
(
2019
).
9.
A. B.
Tabrizi
,
J.
Whale
,
T.
Lyons
et al, “
Extent to which international wind turbine design standard, IEC61400-2 is valid for a rooftop wind installation
,”
J. Wind Eng. Ind. Aerodyn.
139
,
50
61
(
2015
).
10.
Q.
Li
,
J.
Murata
,
M.
Endo
et al, “
Experimental and numerical investigation of the effect of turbulent inflow on a horizontal axis wind turbine (Part I: Power performance)
,”
Energy
113
,
713
722
(
2016
).
11.
M.
Talavera
and
F.
Shu
, “
Experimental study of turbulence intensity influence on wind turbine performance and wake recovery in a low-speed wind tunnel
,”
Renewable Energy
109
,
363
371
(
2017
).
12.
J. W.
Yang
,
H.
Yang
,
W. J.
Zhu
et al, “
Experimental study on aerodynamic characteristics of a gurney flap on a wind turbine airfoil under high turbulent flow condition
,”
Appl. Sci.
10
(
20
),
7258
(
2020
).
13.
U.
Fernandez-Gamiz
,
E.
Zulueta
,
A.
Boyano
et al, “
Five megawatt wind turbine power output improvements by passive flow control devices
,”
Energies
10
(
6
),
742
(
2017
).
14.
J.
Alber
,
G.
Pechlivanoglou
,
C. O.
Paschereit
et al,
2017
. “
Parametric investigation of gurney flaps for the use on wind turbine blades
,” in
ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition
,
Charlotte, North Carolina, USA
(
ASME
, 2017), Paper No. GT2017-64475.
15.
T.
Amoretti
,
F.
Huet
,
P.
Garambois
et al, “
Configurable dual rotor wind turbine model based on BEM method: Co-rotating and counter-rotating comparison
,”
Energy Convers. Manage.
293
,
117461
(
2023
).
16.
Y.
Yan
,
E. J.
Avital
,
J.
Williams
et al, “
Performance improvements for a vertical axis wind turbine by means of Gurney flap
,”
J. Fluids Eng.
142
(
2
),
021205
(
2020
).
17.
Q.
Liu
,
W.
Miao
,
Q.
Ye
et al, “
Performance assessment of an innovative Gurney flap for straight-bladed vertical axis wind turbine
,”
Renewable Energy
185
,
1124
1138
(
2022
).
18.
A.
Ebrahimi
and
M.
Movahhedi
, “
Wind turbine power improvement utilizing passive flow control with microtab
,”
Energy
150
,
575
582
(
2018
).
19.
Y.
Zhang
,
V.
Ramdoss
,
Z.
Saleem
et al, “
Effects of root Gurney flaps on the aerodynamic performance of a horizontal axis wind turbine
,”
Energy
187
,
115955
(
2019
).
20.
C.
Bak
,
F.
Zahle
,
R.
Bitsche
et al, “
The DTU 10-MW reference wind turbine
,” Report No. I-0092 (
DTU Wind Energy
,
Denmark
,
2013
).
21.
J.
Nelson
and
N.
Koratkar
, “
Effect of miniaturized Gurney flaps on aerodynamic performance of microscale rotors
,”
J. Aircr.
42
(
2
),
557
561
(
2005
).
22.
J. A. C.
Kentfield
, “
The influence of free-stream turbulence intensity on the performance of Gurney-flap equipped wind-turbine blades
,”
Wind Eng.
20
(
2
),
93
106
(
1996
).
23.
J.
Alber
,
R.
Soto-Valle
,
M.
Manolesos
et al, “
Aerodynamic effects of Gurney flaps on the rotor blades of a research wind turbine
,”
Wind Energy Sci.
5
(
4
),
1645
1662
(
2020
).
24.
H. C.
Zhou
,
Z.
Jiang
,
G. L.
Wang
et al, “
Aerodynamic characteristics of isolated loaded tires with different tread patterns: Experiment and simulation
,”
Chin. J. Mech. Eng.
34
(
2
),
6
(
2021
).
25.
R. Z.
Gao
,
J. W.
Yang
,
H.
Yang
et al, “
Wind-tunnel experimental study on aeroelastic response of flexible wind turbine blades under different wind conditions
,”
Renewable Energy
219
,
119539
(
2023
).
26.
M.
Sessarego
,
N.
Ramos-Garcia
,
H.
Yang
et al, “
Aerodynamic wind-turbine rotor design using surrogate modeling and three-dimensional viscous-inviscid interaction technique
,”
Renewable Energy
93
,
620
635
(
2016
).
27.
F.
Zahle
,
C.
Bak
,
N. N.
Sørensen
et al, “
Comprehensive aerodynamic analysis of a 10 MW wind turbine rotor using 3D CFD
,” AIAA Paper No. 2014-0359, 2014.
28.
B.
Dou
,
M.
Guala
,
P.
Zeng
et al, “
Experimental investigation of the power performance of a minimal wind turbine array in an atmospheric boundary layer wind tunnel
,”
Energy Convers. Manage.
196
,
906
919
(
2019
).
29.
S.
Fu
,
B.
Zhang
,
Y.
Zheng
et al, “
In-phase and out-of-phase pitch and roll oscillations of model wind turbines within uniform arrays
,”
Appl. Energy
269
,
114921
(
2020
).
30.
M.
Bastankhah
and
P. A.
Fernando
, “
A new miniature wind turbine for wind tunnel experiments. Part I: Design and performance
,”
Energies
10
(
7
),
923
(
2017
).
31.
X. X.
Huang
,
J. W.
Yang
,
Z. Y.
Gao
et al, “
Output power and wake flow characteristics of a wind turbine with swept blades
,”
Machines
10
(
10
),
876
(
2022
).
32.
C. R.
Chu
and
P. H.
Chiang
, “
Turbulence effects on the wake flow and power production of a horizontal-axis wind turbine
,”
J. Wind Eng. Ind. Aerodyn.
124
,
82
89
(
2014
).
33.
H.
Wang
,
T. G.
Wang
,
S. T.
Ke
et al, “
Assessing code-based design wind loads for offshore wind turbines in China against typhoons
,”
Renewable Energy
212
,
669
682
(
2023
).
34.
P.
He
and
J.
Xia
, “
Aeroelastic model of flexible blades of wind turbines under complex wind speed profiles
,”
Acta Mech. Sin.
39
(
9
),
322477
(
2023
).
35.
J.
Whale
,
M. P.
McHenry
, and
A.
Malla
, “
Scheduling and conducting power performance testing of a small wind turbine
,”
Renewable Energy
55
,
55
61
(
2013
).
36.
H.
Meng
,
Z.
Ma
,
B.
Dou
et al, “
Investigation on the performance of a novel forward-folding rotor used in a downwind horizontal-axis turbine
,”
Energy
190
,
116384
(
2020
).
37.
M.
Kulak
,
M.
Lipian
, and
K.
Zawadzki
, “
Investigation of performance of small wind turbine blades with winglets
,”
Int. J. Numer. Methods Heat Fluid Flow
31
(
2
),
629
640
(
2021
).
38.
L. R.
Chamorro
,
R. E. A.
Arndt
, and
F.
Sotiropoulos
, “
Reynolds number dependence of turbulence statistics in the wake of wind turbines
,”
Wind Energy
15
(
5
),
733
742
(
2012
).
39.
M.
Bourhis
,
M.
Pereira
, and
F.
Ravelet
, “
Experimental investigation of the effects of the Reynolds number on the performance and near wake of a wind turbine
,”
Renewable Energy
209
,
63
70
(
2023
).
40.
Q.
Li
,
Y.
Kamada
,
T.
Maeda
et al, “
Experimental investigations of boundary layer impact on the airfoil aerodynamic forces of horizontal axis wind turbine in turbulent inflows
,”
Energy
135
,
799
810
(
2017
).
41.
A.
Zanotti
and
G.
Gibertini
, “
Experimental assessment of an active L-shaped tab for dynamic stall control
,”
J. Fluids Struct.
77
,
151
169
(
2018
).
42.
J. W.
Yang
,
H.
Yang
, and
X. J.
Wang
, “
Aerodynamic modeling of wind turbine airfoil concerning dynamic stall and Gurney flap
,”
Acta Mech. Sin.
39
,
323056
(
2023
).
43.
H. W.
Liu
,
Y. Q.
Jin
,
N.
Tobin
et al, “
Towards uncovering the structure of power fluctuations of wind farms
,”
Phys. Rev. E
96
,
063117
(
2017
).
44.
G.
Deskos
,
G.
Payne
,
B.
Gaurier
et al, “
On the spectral behaviour of the turbulence-driven power fluctuations of horizontal-axis turbines
,”
J. Fluid Mech.
904
,
A13
(
2020
).
45.
W.
Tian
,
A.
Ozbay
, and
H.
Hu
, “
A wind tunnel study of wind loads on a model wind turbine in atmospheric boundary layer winds
,”
J. Fluids Struct.
85
,
17
26
(
2019
).
46.
Z. Y.
Wang
,
W.
Tian
, and
H.
Hu
, “
A comparative study on the aeromechanic performances of upwind and downwind horizontal-axis wind turbines
,”
Energy Convers. Manage.
163
,
100
110
(
2018
).
47.
S.
Gambuzza
and
B.
Ganapathisubramani
, “
The effects of free-stream turbulence on the performance of a model wind turbine
,”
J. Renewable Sustainable Energy
13
,
023304
(
2021
).
You do not currently have access to this content.