Abstract

Froude scaling for Floating Offshore Wind Turbine (FOWT) platforms is typical for understanding and interpreting their behavior and subsequent designs for testing in wave basins. Despite its popularity, the variability and uncertainty of the kinetic responses of such floating structures as a function of scaling require more attention. This work addresses the question of consistency of Froude scaling by comparing the hydrodynamic responses of a range of DeepCwind semisubmersible FOWT scaled models (full model, 1/2, 1/4, 1/9, 1/16, 1/25, 1/36, 1/49, and 1/50). The comparison was made both in the mooring-line tension and bending moment of structural members, which are directly related to their safety limit states. Hydrodynamic forces due to diffraction, radiation, and viscosity along with hydrostatic forces and mooring boundaries are modeled by ansys-Aqwa, which were subsequently converted to bending moment estimates. The variability of kinetic responses like mooring-line tensions and bending moment estimates was investigated for each scaled model, along with the identification of regions of inconsistencies. In the context of offshore renewable energy development through technological readiness levels, the study is especially pertinent for understanding how force variabilities and uncertainties are related to these kinetic responses of semisubmersible platforms.

References

1.
Sadradin
,
H. L.
, and
Shao
,
X.
,
2022
, “
State-of-the-Art of Experimental Methods for Floating Wind Turbines
,”
J. Renew. Sustain. Energy
,
14
(
3
), p.
032701
.
2.
Pham
,
T. D.
, and
Shin
,
H.
,
2019
, “
Validation of a 750 kW Semi-Submersible Floating Offshore Wind Turbine Numerical Model With Model Test Data, Part I: Model-I
,”
Int. J. Nav. Archit. Ocean Eng.
,
11
(
2
), pp.
980
992
.
3.
Borisade
,
F.
,
Koch
,
C.
,
Lemmer
,
F.
,
Cheng
,
P. W.
,
Campagnolo
,
F.
, and
Matha
,
D.
,
2018
, “
Validation of INWIND.EU Scaled Model Test of a Semisubmersible Floating Wind Turbine
,”
Int. J. Offshore Polar Eng.
,
28
(1), pp.
54
64
.
4.
Roddier
,
D.
,
Cermelli
,
C.
,
Aubault
,
A.
, and
Weinstein
,
A.
,
2010
, “
WindFloat: A Floating Foundation for Offshore Wind Turbines
,”
J. Renew. Sustain. Energy
,
2
(
3
), p.
033104
.
5.
Duan
,
F.
,
Hu
,
Z.
, and
Niedzwecki
,
M.
,
2016
, “
Model Test Investigation of a Spar Floating Wind Turbine
,”
Mar. Struct.
,
49
, pp.
76
96
.
6.
Bachynski
,
E. E.
,
Thys
,
M.
,
Sauder
,
T.
,
Chabaud
,
V.
, and
Saether
,
L. O.
,
2016
, “
Real-Time Hybrid Model Testing of a Braceless Semi-Submersible Wind Turbine. Part II: Experimental Result
,”
Proceedings of the ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering
,
Busan, South Korea
,
June 19–24
.
7.
Kitney
,
N.
, and
Brown
,
D. T.
,
2001
, “
Experimental Investigation of Mooring Line Loading Using Large and Small-Scale Models
,”
ASME J. Offshore Mech. Arct. Eng.
,
123
(
1
), pp.
1
9
.
8.
Garbatov
,
Y.
,
Saad-Eldeen
,
S.
, and
Guedes Soares
,
C.
,
2015
, “
Hull Girder Ultimate Strength Assessment Based on Experimental Results and the Dimensional Theory
,”
Eng. Struct.
,
100
, pp.
742
750
.
9.
Wang
,
Q.
, and
Wang
,
D.
,
2020
, “
Scaling Characteristic of Hull Girder's Ultimate Strength and Failure Behaviors: an Empirically Modified Scaling Criterion
,”
Ocean Eng.
,
212
, p.
107595
.
10.
ANSYS
,
2020
,
Aqwa Theory Manual
,
Ansys, Inc.
,
Canonsburg, PA
.
11.
Suzuki
,
H.
,
Xiong
,
J.
,
do Carmo
,
L.H.
,
Vieira
,
D.P.
,
de Mello
,
P.C.
,
Malta
,
E.B.
, and
Simos
,
A.N.
,
2019
, “
Elastic Response of a Light-Weight Floating Support Structure of FOWT With Guywire Supported Tower
,”
J. Mar. Sci. Technol.
,
24
(
4
), pp.
1015
1028
.
12.
Suzuki
,
H.
,
Shiohara
,
H.
,
Schnepf
,
A.
,
Houtani
,
H.
,
Carmo
,
L. H.
,
Hirabayashi
,
S.
,
Haneda
,
K.
, et al
,
2020
, “
Wave and Wind Responses of a Very-Light Fowt With Guy-Wired-Supported Tower: Numerical and Experimental Studies
,”
J. Mar. Sci. Eng.
,
8
(
11
), p.
841
.
13.
Liu
,
Y.
, and
Ishihara
,
T.
,
2020
, “
Numerical Study on Sectional Loads and Structural Optimization of an Elastic Semi-Submersible Floating Platform
,”
Energies
,
14
(
1
), p.
182
.
14.
Jain
,
A.
,
Robertson
,
A. N.
,
Jonkman
,
J. M.
,
Goupee
,
A. J.
,
Kimbali
,
R. W.
, and
Swift
,
A. H.
,
2012
, “
FAST Code Verification of Scaling Laws for DeepCwind Floating Wind System Tests
,”
22nd International Offshore and Polar Engineering Conference
,
Rhodes, Greece
,
June 17–22
.
15.
Robertson
,
A. N.
,
Wendt
,
F.
,
Jonkman
,
J. M.
,
Popko
,
W.
,
Dagher
,
H.
,
Gueydon
,
S.
,
Qvist
,
J.
, et al
,
2017
, “
OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible WInd Turbine
,”
Energy Procedia
,
137
, pp.
38
57
.
16.
Luan
,
C.
,
Chabaud
,
V.
,
Bachynski
,
E. E.
,
Gao
,
Z.
, and
Moan
,
T.
,
2017
, “
Experimental Validation of a Time-Domain Approach for Determining Sectional Loads in a Floating Wind Turbine Hull Subjected to Moderate Waves
,”
Energy Procedia
,
137
, pp.
366
381
.
17.
R. P. a. G. ITTC (International Towing Tank Conference)
,
2011
, “
Global Loads Seakeeping Procedure
,”
Proceedings of the 26th ITTC Seakeeping Committee
,
Rio de Janeiro, Brazil
,
Aug. 28–Sept. 1
.
18.
Plate
,
E. J.
, and
Nath
,
H. J.
,
1968
, “
Modelling of Structures Subjected to Wind Generated Waves
,”
11th International Conference on Coastal Engineering
,
London
,
Sept. 1
.
19.
Dalzell
,
J.
,
1964
, “
An Investigation of Midship Bending Moments Experienced in Extreme Regular Waves by Models of Mariner-Type Ship and Three Variants
,”
Ship Structure Committee
,
Washington, DC
.
20.
Numata
,
E.
, and
Yonkers
,
W. F.
,
1969
, “
Midship Wave Bending Moments in a Model of the Mariner-Class Cargo Ship “California Bear” Running at Oblique Headings in Regular Waves
,”
Ship Structure Committee
,
Washington, DC.
21.
Chiocco
,
M. J.
, and
Numata
,
E.
,
1969
, “
Midship Wave Bending Moments in a Model of the Cargo Ship “Wolverine State” Running at Oblique Heading in Regular Waves
,”
Ship Structure Committee
,
Washington, DC.
22.
Dalzell
,
J. F.
, and
Chiocco
,
M.
,
1973
, “
Wave Loads in a Model of the SL-7 Containership Running at Oblique Headings in Regular Waves
,”
Report SSC-239, SL-7-2
.
23.
Maniar
,
N. M.
,
1964
, “
Investigation of Bending Moments Within the Midship Half Length of MARINER Model in Extreme Waves
,”
Report SSC-163, Ship Structure Committee
.
24.
Maniar
,
N. M.
, and
Numata
,
E.
,
1968
, “
Bending Moment Distribution in a Mariner Cargo Ship Model in Regular and Irregular Waves of ExtremeSteepness
,”
Report SSC-190 Ship Structure Committee
.
25.
Harris
,
H. G.
, and
Sabnis
,
G. M.
,
1999
,
Structural Modeling and Experimental Techniques
,
CRC Press
,
Boca Raton, FL
.
26.
Chakrabarti
,
S.
,
1994
,
Offshore Structure Modeling. Advanced Series on Ocean Engineering
, Vol.
9
,
World Scientific Publishing
,
Singapore
.
27.
Bielicki
,
S.
,
2021
, “
Prediction of Ship Motions in Irregular Waves Based on Response Amplitude Operators Evaluated Experimentally in Noise Waves
,”
Pol. Marit. Res.
,
109
(
1
), pp.
16
27
.
28.
Robertson
,
A.
,
Jonkman
,
J.
,
Masciola
,
M.
,
Song
,
H.
,
Goupee
,
A.
,
Coulling
,
A.
, and
Luan
,
C.
,
2014
, “
Definition of the Semisubmersible Floating System for Phase II of OC4
,”
NREL
,
U.S. Department of Energy
,
Denver West Parkway
.
29.
Cummins
,
W. E.
,
1962
, “
The Impulse Response Function and Ship Motions
,”
Report 1661
.
30.
Luan
,
C.
,
Gao
,
Z.
, and
Moan
,
T.
,
2017
, “
Development and Verification of a Time-Domain Approach for Determining Forces and Moments in Structural Components of Floaters With an Application to Floating Wind Turbines
,”
Mar. Struct.
,
51
, pp.
87
109
.
31.
Wright
,
C.
,
Pakrashi
,
V.
, and
Murphy
,
J.
,
2016
, “
Dynamic Effect of Anchor Positional Tolerance on Tension Moored Floating Wind Turbine
,”
J. Phys. Conf. Ser.
,
753
, p.
092019
.
32.
Wright
,
C.
,
O'Sullivan
,
K.
,
Muprhy
,
J.
, and
Pakrashi
,
V.
,
2015
, “
Experimental Comparison of Dynamic Response of a Tension Moored Floating Wind Turbine Platform With and Without Spring Dampers
,”
J. Phys. Conf. Ser.
,
628
, p.
012056
.
33.
Schoefs
,
F.
,
O'Byrne
,
M.
,
Pakrashi
,
V.
,
Ghosh
,
B.
,
Oumouni
,
M.
,
Soulard
,
T.
, and
Reynaud
,
M.
,
2021
, “
Fractal Dimension as an Effective Feature for Characterizing Hard Marine Growth Roughness From Underwater Image Processing in Controlled and Uncontrolled Image Environments
,”
J. Mar. Sci. Eng.
,
9
(
12
), p.
1344
.
34.
O'Leary
,
K.
,
Pakrashi
,
V.
, and
Kelliher
,
D.
,
2019
, “
Optimization of Composite Material Tower for Offshore Wind Turbine Structures
,”
Renew. Energy
,
140
, pp.
928
942
.
35.
O'Kelly-Lynch
,
P.
,
Long
,
C.
,
McAuliffe
,
F. D.
,
Murphy
,
J.
, and
Pakrashi
,
V.
,
2020
, “
Structural Design Implications of Combining a Point Absorber With a Wind Turbine Monopile for the East and West Coast of Ireland
,”
Renew. Sustain. Energy Rev.
,
119
, p.
109583
.
36.
O'Donnell
,
D.
,
Murphy
,
J.
, and
Pakrashi
,
V.
,
2020
, “
Damage Monitoring of a Catenary Moored Spar Platform for Renewable Energy Devices
,”
Energies
,
13
(
14
), p.
3631
.
You do not currently have access to this content.