The accurate prediction of unsteady aerodynamic performance and loads, for floating offshore wind turbines (FOWTs), is still questionable because several conventional methods widely used for this purpose are applied in ways that violate the theoretical assumptions of their original formulation. The major objective of the present study is to investigate the unsteady aerodynamic effects for the rotating blade due to the periodic surge motions of an FOWT. This work was conducted using several numerical approaches, particularly unsteady computational fluid dynamics (CFD) with an overset grid-based approach. The unsteady aerodynamic effects that occur when an FOWT is subjected to the surge motion of its floating support platform is assumed as a sinusoidal function. The present CFD simulation based on an overset grid approach provides a sophisticated numerical model on complex flows around the rotating blades simultaneously having the platform surge motion. In addition, an in-house unsteady blade element momentum (UBEM) and the fast (fatigue, aerodynamic, structure, and turbulence) codes are also applied as conventional approaches. The unsteady aerodynamic performances and loads of the rotating blade are shown to be changed considerably depending on the amplitude and frequency of the platform surge motion. The results for the flow interaction phenomena between the oscillating motions of the rotating wind turbine blades and the generated blade-tip vortices are presented and investigated in detail.

References

References
1.
Archer
,
C. L.
, and
Jacobson
,
M. Z.
,
2005
, “
Evaluation of Global Wind Power
,”
J. Geophys. Res.
,
110
(
D12
), p.
D12110
.
2.
Butterfield
,
S.
,
Musical
,
W.
,
Jonkman
,
J.
,
Sclavounos
,
P.
, and
Wayman
,
L.
,
2005
, “
Engineering Challenges for Floating Offshore Wind Turbines
,”
Copenhagen Offshore Wind International Conference and Expedition
(
COW05
),
Copenhagen, Denmark
, Oct. 26–28.
3.
Mostafa
,
N.
,
Murai
,
M.
,
Nishimura
,
R.
,
Fujita
,
O.
, and
Nihei
,
Y.
,
2012
, “
Study of Motion of Spar-Type Floating Wind Turbines in Waves With Effect of Gyro Moment at Inclination
,”
J. Nav. Archit. Mar. Eng.
,
9
(
1
), pp.
67
79
.
4.
de Vaal
,
J. B.
,
Hansen
,
M. O. L.
, and
Moan
,
T.
,
2014
, “
Effect of Wind Turbine Surge Motion on Rotor Thrust and Induced Velocity
,”
Wind Energy
,
17
(
1
), pp.
105
121
.
5.
Moriarty
,
P. J.
, and
Hansen
,
C. A.
,
2002
, “
AeroDyn Theory Manual
,” National Renewable Energy Laboratory, Golden, CO, Technical Report No. NREL/EL-500-36881.
6.
Laino
,
D. J.
, and
Craig Hansen
,
A.
,
2002
, “
AeroDyn User Guide, Version 12.50
,” Windward Engineering, Salt Lake City, UT.
7.
Sebastian
,
T.
,
2012
, “
The Aerodynamic and Near Wake of an Offshore Floating Horizontal Axis Wind Turbine
,” Ph.D. thesis, University of Massachusetts, Amherst, MA.
8.
Sebastian
,
T.
, and
Lackner
,
M. A.
,
2012
, “
Analysis of the Induction and Wake Evolution of an Offshore Floating Wind Turbine
,”
Energies
,
5
(
4
), pp.
968
1000
.
9.
Sebastian
,
T.
, and
Lackner
,
M. A.
,
2012
, “
Development of a Free Vortex Wake Method Code for Offshore Floating Wind Turbines
,”
Renewable Energy
,
46
, pp.
269
275
.
10.
Sebastian
,
T.
, and
Lackner
,
M. A.
,
2012
, “
Characterization of the Unsteady Aerodynamics of Offshore Floating Wind Turbines
,”
Wind Energy
,
16
(
3
), pp.
339
352
.
11.
Corbetta
, G.
,
2013
, “
The European Offshore Wind Industry—Key Trends and Statistics 1st Half 2013
,” European Wind Energy Association, Brussels, Belgium, http://www.ewea.org/fileadmin/files/library/publications/statistics/EWEA_OffshoreStats_July2013.pdf
12.
Tran
,
T. T.
,
Kim
,
D. H.
, and
Bae
,
K. S.
,
2013
, “
Extreme Load Estimation for a Large Wind Turbine Using CFD and Unsteady BEM
,” 13th International Conference on Computational Science and Its Applications (
ICCSA2013
), Ho Chi Minh City, Vietnam, June 24-27, pp.
127
142
.
13.
Jonkman
,
J. M.
,
2009
, “
Dynamics of Offshore Floating Wind Turbines—Model Development and Verification
,”
Wind Energy
,
12
(
5
), pp.
459
492
.
14.
Demirdzic
,
I.
,
Lilek
,
Z.
, and
Peric
,
M.
,
1993
, “
A Collocated Finite Volume Method for Predicting Flows at all Speeds
,”
Int. J. Numer. Methods Fluids
,
16
(
12
), pp.
1029
1050
.
15.
Demirdzic
,
I.
, and
Muzaferija
,
S.
,
1995
, “
Numerical Method for Coupled Fluid Flow, Heat Transfer and Stress Analysis Using Unstructured Moving Meshes With Cells of Arbitrary Topology
,”
Comput. Methods Appl. Mech. Eng.
,
125
(
1–4
), pp.
235
255
.
16.
Ferziger
,
J. H.
, and
Peric
,
M.
,
2002
, Computational Methods for Fluid Dynamics,
3rd rev. ed.
,
Springer-Verlag
,
Berlin
.
17.
Sarun
,
B.
,
2006
, “
Computational Studies of Horizontal Axis Wind Turbines in High Wind Speed Condition Using Advanced Turbulence Models
,” Ph.D. thesis, Georgia Institute of Technology, Atlanta, GA.
18.
Hadzic
,
H.
,
2005
, “
Development and Application of Finite Volume Method for the Computation of Flows Around Moving Bodies on Unstructured, Overlapping Grids
,” Ph.D. thesis, Technical University Hamburg-Harburg, Harburg, Germany.
19.
Hansen
,
M. O. L.
,
2000
, Aerodynamics of Wind Turbines,
James and James, Science Publishers
,
Sterling, VA
.
20.
Snel
,
H.
,
Houwink
,
R.
, and
Bosschers
,
J.
,
1994
, “
Sectional Prediction of Lift Coefficients on Rotating Wind Turbine Blades in Stall
,” Netherlands Energy Research Foundation, Petten, The Netherlands, Report No. ECN-C-93-052.
21.
Lindenburg
,
C.
,
2004
, “
Modeling of Rotational Augmentation Based on Engineering Considerations and Measurements
,”
European Wind Energy Conference
,
London
, Nov. 22–25, Paper No. ECN-RX-04-131..
22.
Øye
,
S.
,
1994
, “
Dynamic Stall Simulated as a Time Lag of Separation
,”
4th IEA Symposium on the Aerodynamics of Wind Turbines
, Rome, Nov. 20–21,
K. F.
McAnulty
, ed.,
Harwell Laboratory
,
Harwell, UK
, Paper No. ETSU-N-118.
23.
Jonkman
,
J.
,
Butterfield
,
S.
,
Musial
,
W.
, and
Scott
,
G.
,
2009
, “
Definition of a 5 MW Reference Wind Turbine for Offshore System Development
,” National Renewable Energy Laboratory, Golden, CO, Technical Report No. NREL/TP-500-38060.
24.
Bazilevs
,
Y.
,
Hsu
,
M. C.
,
Akkerman
,
I.
,
Wright
,
S.
,
Kakizawa
,
K.
,
Henicke
,
B.
,
Spielman
,
T.
, and
Tezduyar
,
T. E.
,
2011
, “
3D Simulation of Wind Turbine Rotors at Full Scale. Part I: Geometry Modeling and Aerodynamics
,”
Int. J. Numer. Methods Fluids
,
65
(
1–3
), pp.
207
235
.
25.
Wayman
,
E.
,
2006
, “
Coupled Dynamics and Economic Analysis of Floating Wind Turbine Systems
,” Ph.D. thesis, Massachusetts Institute of Technology, Cambridge, MA.
26.
Chaney
,
E.
,
Eggers
,
A.
,
Moriarty
,
P.
, and
Holley
,
W.
,
2001
, “
Skewed Wake Induction Effects on Thrust Distribution on Small Wind Turbine Rotors
,”
ASME J. Sol. Energy Eng.
,
123
(
4
), pp.
290
295
.
27.
Davis
,
D.
, and
Hansen
,
A.
,
2002
, “
Operation and Load Measurements During Extreme Wind Events for a Southwest Windpower Whisper h40
,”
Windpower 2002
,
American Wind Energy Association
,
Portland, OR
.
28.
Corbus
,
D.
,
Hansen
,
A.
, and
Minnema
,
J.
,
2006
, “
Effect of Blade Torsion Effects on Modeling Results for the Small Wind Research Turbine (SWRT)
,”
AIAA
Paper No. 2006-787.
29.
Vermeera
,
L. J.
,
Sørensen
,
J. N.
, and
Crespoc
,
A.
,
2003
, “
Wind Turbine Wake Aerodynamics
,”
Prog. Aerosp. Sci.
,
39
(
6–7
), pp.
467
510
.
30.
Leishman
,
J.
,
2006
,
Principles of Helicopter Aerodynamics
,
Cambridge University Press
,
New York
, Chap. 9.
31.
Pereira
,
R.
,
Schepers
,
G.
, and
Pavel
,
M. D.
,
2013
, “
Validation of the Beddoes–Leishman Dynamic Stall Model for Horizontal Axis Wind Turbines Using MEXICO Data
,”
Wind Energy
,
16
(
2
), pp.
207
219
.
32.
Minnema
,
J. E.
,
1998
, “
Pitching Moment Predictions on Wind Turbine Blades Using the Beddoes–Leishman Model for Unsteady Aerodynamics and Dynamic Stall
,” Master's thesis, Department of Mechanical Engineering, University of Utah, Salt Lake City, UT.
33.
Pierce
,
K. G.
,
1996
, “
Wind Turbine Load Prediction Using the Beddoes–Leishman Model for Unsteady Aerodynamics and Dynamic Stall
,” Master's thesis, Department of Mechanical Engineering, University of Utah, Salt Lake City, UT.
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