Post on 17-Jul-2020
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
OC5 Project Phase Ib: Validation of Hydrodynamic Loading on
a Fixed, Flexible Cylinder for Offshore Wind Applications
DeepWind Conference – Trondheim, Norway
Amy Robertson January 21, 2016
2
Co-Authors • Fabian F. Wendt - National Renewable Energy Laboratory, Colorado, USA • Jason M. Jonkman - National Renewable Energy Laboratory, Colorado, USA • Wojciech Popko - Fraunhofer IWES, Germany • Henrik Bredmose – Technical University of Denmark, Denmark • Michael Borg - Technical University of Denmark, Denmark • Flemming Schlutter - Technical University of Denmark, Denmark • Jacob Qvist - 4Subsea, Norway • Roger Bergua - Alstom Wind, Spain • Rob Harries - DNV GL, England • Anders Yde - Technical University of Denmark, Denmark • Tor Anders Nygaard - Institute for Energy Technology, Norway • Luca Oggiano - Institute for Energy Technology, Norway • Pauline Bozonnet - IFP Energies nouvelles, France • Ludovic Bouy - PRINCIPIA, France • Carlos Barrera Sanchez - Universidad de Cantabria – IH Cantabria, Spain • Raul Guanche García - Universidad de Cantabria – IH Cantabria, Spain • Erin E. Bachynski - MARINTEK, Norway • Ying Tu - Norwegian University of Science and Technology, Norway • Ilmas Bayati - Politecnico di Milano, Italy • Friedemann Beyer - Stuttgart Wind Energy, University of Stuttgart, Germany • Hyunkyoung Shin - University of Ulsan, Korea • Matthieu Guerinel - WavEC Offshore Renewables, Portugal • Tjeerd van der Zee - Knowledge Centre WMC, the Netherlands
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IEA Wind Tasks 23 and 30 (OC3/OC4/OC5)
• Verification and validation of offshore wind modeling tools are need to ensure their accuracy, and give confidence in their usefulness to users.
• Three research projects were initiated under IEA Wind to address this need:
OC3 = Offshore Code Comparison Collaboration (2005-2009) OC4 = Offshore Code Comparison Collaboration, Continuation (2010-2013) OC5 = Offshore Code Comparison Collaboration, Continuation, with
Correlation (2014-2017)
4
OC5 Project Phases
Phase I: Monopile - Tank Testing
Phase II: Semi - Tank Testing
Phase III: Jacket/Tripod – Open Ocean
• OC3 and OC4 focused on verifying tools (tool-to-tool comparisons) • OC5 focuses on validating tools (code-to-data comparisons)
5
OC5 Phase Ib
• Objective: validate hydrodynamic loads and acceleration response for a fixed, flexible cylinder
• Test Data from Wave Loads Project: o 3-year project with goal of improving
numerical models for wave loads on offshore wind turbines
o Carried out collaboratively by DTU Wind Energy, DTU Mechanical Engineering, and DHI
o Performed at shallow-water basin at DHI o Thank you to: Ole Petersen at DHI and
Henrik Bredmose and Michael Borg at DTU for graciously supplying the data and information needed for this phase of the OC5 project.
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Test Set-Up
• 1:80 scale, flexible cylinder • On slope – to create steep waves • Tests done at two water depths:
0.51 m and 0.26 m (40 and 20 m full scale)
• Measurements used: o Wave elevation o Acceleration at top mass of cylinder o Total hydrodynamic force on cylinder
7
Tests Simulated
• 7 Datasets were examined: o 4 regular cases
– 2 water depths – 2 wave heights
o 3 irregular cases – 2 water depths – 2 wave heights
• First regular wave case used for calibration
Test # Wave Type Water Depth (m) H/Hs (m) T/Tp (s) Gamma CA CD
1 Regular 0.51 0.090 1.5655 1.22 1.0
2 Regular 0.51 0.118 1.5655 1.22 1.0
3 Irregular 0.51 0.104 1.40 3.3 1.0 1.0
4 Irregular 0.51 0.140 1.55 3.3 1.0 1.0
5 Regular 0.26 0.086 1.565 1.22 1.0
6 Regular 0.26 0.121 1.565 1.22 1.0
7 Irregular 0.26 0.133 1.560 3.3 1.0 1.0
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Summary of Tools and Modeling Approach Participant Code Wave Model (Reg/Irr) Wave Elevation Hydro Model
Structural Model Number DOFs
4Subsea OrcaFlex FNPF kinematics FNPF kinematics ME FE, RDS 160 elements 960 DOFs GE SAMCEF Wind Turbines (S4WT) 5
th Order Stokes/ Linear Airy Stretching ME FE (TS), RD 13 elements 84 DOF DNV GL-ME Bladed 4.6 6
th and 8th Order SF/ Linear Airy Measured ME FE (TS), MD 8 (CB)
DNV GL-PF Bladed 4.6 Linear Airy Measured 1st Order PF Rigid N/A
DTU-HAWC2 HAWC2 6th and 8th Order SF/L. Airy & FNPF kinematics Stretching & FNPF kin. ME FE (TS), RDS
20 elements, 126 DOF
DTU-HAWC2-PF HAWC2 6th and 8th Order SF/L. Airy Stretching 1st Order PF FE (TS), RDS 31 elements, 192 DOF DTU-BEAM OceanWave3D FNPF kinematics FNPF kinematics ME+Rainey FE (EB), RD 160 DOFs
IFE 3Dfloat FNPF kinematics FNPF kinematics ME FE (EB), RDS 62 elements, 378 DOF IFE-CFD STAR CCM CFD CFD-derived CFD Rigid N/A
IFP-PRI DeeplinesWind 3rd Ord. SF/ Linear Airy Measured ME FE 200 elements
UC-IHC IH2VOF FNPF kinematics FNPF kinematics ME Rigid N/A
MARINTEK RIFLEX 2nd Order Stokes & FNPF
kinematics Measured & FNPF kin. ME
FE(E-B), RDS, FS
167 elements, 1002 DOF
NREL-ME FAST 2nd Order Stokes & FNPF
kinematics Measured & FNPF kin. ME FE (TS), MD 4 (CB)
NREL-PF FAST 2nd Order Stokes Measured 2nd Order PF Rigid N/A
NTNU-Lin FEDEM 7.1 Linear Airy None ME FE (EB), RD 13 elements, 84 DOF
NTNU-Stokes5 FEDEM 7.1 5th Order Stokes None ME FE (EB), RD 13 elements, 84 DOF
NTNU-Stream FEDEM 7.1 Stream Function None ME FE (EB), RD 13 elements, 84 DOF
PoliMi POLI-HydroWind 2nd Order Stokes None ME FE (EB), RD 23 elements, 69 DOF
SWE SIMPACK +HydroDyn 2nd Order Stokes None ME FE (TS), MD 50
UOU UOU + FAST 2nd Order Stokes None ME Rigid N/A
WavEC Wavec2Wire 2nd Order Stokes /Linear Airy Measured 2nd/1st Order PF Rigid N/A
WMC FOCUS6 (PHATAS) FNPF kinematics FNPF kinematics ME FE (TS), MD 12 (CB)
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Calibration
• Group calibrated CA and CD coefficients based on Test 1, to get appropriate levels of force o All participants used same values
to have consistency in model parameters – to better see differences in modeling approach
• A CA value of 1.22 was required, which is larger than expected o Suspect the higher measured loads
might be due to reflected waves that were not modeled in the simulation
212 4D M
DF C Du u C uπρ ρ= +
Morison’s Equation
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Test 1 – Regular Wave – Deeper Water - Force Results
Time (s)
70 70.5 71 71.5 72 72.5 73 73.5 74 74.5 75
Tota
l for
ce (N
)
-4
-2
0
2
4
6Test 1, 0.51 m water depth, H = 0.09 m, T = 1.5655 s
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kinDTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kinEXPERIMENTIFE-CFDIFE-kinIFP-PRI-elvMARINTEK-elvMARINTEK-kinNREL-MENREL-ME-elv1NREL-ME-elv2NREL-ME-kinNREL-PFNREL-PF-elv1NREL-PF-elv2NTNU-LinNTNU-Stokes5NTNU-StreamPOLIMISWEUOUWMC-kin4Subsea-kinGEUC-IHC-kinWavEC
Frequency (Hz)
0 0.5 1 1.5 2 2.5 3
Tota
l for
ce (N
)2
/Hz
100
200
300
400
500
600
700
800
11
Test 6 – Regular Wave – Shallower Water - Force Results
Time (s)
70 70.5 71 71.5 72 72.5 73 73.5 74 74.5 75
Tota
l for
ce (N
)
-10
-5
0
5
10Test 6, 0.26 m water depth, H = 0.086 m. T = 1.565 s
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kinDTU-HAWC2DTU-HAWC2-kinEXPERIMENTIFE-kinMARINTEK-elvNREL-MENREL-ME-elv1NREL-ME-elv2NREL-ME-kinNREL-PFNREL-PF-elv1NREL-PF-elv2NTNU-LinNTNU-Stokes5NTNU-StreamPOLIMISWE4Subsea-kinGEUC-IHC-kinWavEC
Frequency (Hz)
0 0.5 1 1.5 2 2.5 3
Tota
l for
ce (N
)2
/Hz
100
200
300
400
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1st Peak Force Component
Deeper Water Depth
Shallower Water Depth
Peak Force1 (N)0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kin
EXPERIMENTIFE-CFD
IFE-kinIFP-PRI-elv
MARINTEK-elvMARINTEK-kin
NREL-MENREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWEUOU
WMC-kin4Subsea-kin
GEUC-IHC-kin
WavEC
Test 1, 0.51 m water depth, H = 0.09 m, T = 1.5655 s
Peak Force1 (N)0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kin
EXPERIMENTIFE-CFD
IFE-kinIFP-PRI-elv
MARINTEK-elvMARINTEK-kin
NREL-MENREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWEUOU
WMC-kin4Subsea-kin
GEUC-IHC-kin
WavEC
Test 2, 0.51 m water depth, H = 0.118 m, T = 1.5655 s
Peak Force1 (N)0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-kin
EXPERIMENTIFE-kin
MARINTEK-elvNREL-ME
NREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWE
4Subsea-kinGE
UC-IHC-kinWavEC
Test 5, 0.26 m water depth, H = 0.086 m, T = 1.565 s
Peak Force1 (N)0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-kin
EXPERIMENTIFE-kin
MARINTEK-elvNREL-ME
NREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWE
4Subsea-kinGE
UC-IHC-kinWavEC
Test 6, 0.26 m water depth, H = 0.121 m, T = 1.560 s
13
2nd Peak Force Component
Deeper Water Depth
Shallower Water Depth
Peak Force2 (N)0 0.5 1 1.5 2 2.5 3 3.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kin
EXPERIMENTIFE-CFD
IFE-kinIFP-PRI-elv
MARINTEK-elvMARINTEK-kin
NREL-MENREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWEUOU
WMC-kin4Subsea-kin
GEUC-IHC-kin
WavEC
Test 1, 0.51 m water depth, H = 0.09 m, T = 1.5655 s
Peak Force2 (N)0 0.5 1 1.5 2 2.5 3 3.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kin
EXPERIMENTIFE-CFD
IFE-kinIFP-PRI-elv
MARINTEK-elvMARINTEK-kin
NREL-MENREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWEUOU
WMC-kin4Subsea-kin
GEUC-IHC-kin
WavEC
Test 2, 0.51 m water depth, H = 0.118 m, T = 1.5655 s
Peak Force2 (N)0 0.5 1 1.5 2 2.5 3 3.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-kin
EXPERIMENTIFE-kin
MARINTEK-elvNREL-ME
NREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWE
4Subsea-kinGE
UC-IHC-kinWavEC
Test 5, 0.26 m water depth, H = 0.086 m, T = 1.565 s
Peak Force2 (N)0 0.5 1 1.5 2 2.5 3 3.5
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-kin
EXPERIMENTIFE-kin
MARINTEK-elvNREL-ME
NREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWE
4Subsea-kinGE
UC-IHC-kinWavEC
Test 6, 0.26 m water depth, H = 0.121 m, T = 1.560 s
14
3rd Peak Force Component
Deeper Water Depth
Shallower Water Depth
Peak Force3 (N)0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kin
EXPERIMENTIFE-CFD
IFE-kinIFP-PRI-elv
MARINTEK-elvMARINTEK-kin
NREL-MENREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWEUOU
WMC-kin4Subsea-kin
GEUC-IHC-kin
WavEC
Test 1, 0.51 m water depth, H = 0.09 m, T = 1.5655 s
Peak Force3 (N)0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kin
EXPERIMENTIFE-CFD
IFE-kinIFP-PRI-elv
MARINTEK-elvMARINTEK-kin
NREL-MENREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWEUOU
WMC-kin4Subsea-kin
GEUC-IHC-kin
WavEC
Test 2, 0.51 m water depth, H = 0.118 m, T = 1.5655 s
Peak Force3 (N)0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-kin
EXPERIMENTIFE-kin
MARINTEK-elvNREL-ME
NREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWE
4Subsea-kinGE
UC-IHC-kinWavEC
Test 5, 0.26 m water depth, H = 0.086 m, T = 1.565 s
Peak Force3 (N)0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kin
DTU-HAWC2DTU-HAWC2-kin
EXPERIMENTIFE-kin
MARINTEK-elvNREL-ME
NREL-ME-elv1NREL-ME-elv2
NREL-ME-kinNREL-PF
NREL-PF-elv1NREL-PF-elv2
NTNU-LinNTNU-Stokes5NTNU-Stream
POLIMISWE
4Subsea-kinGE
UC-IHC-kinWavEC
Test 6, 0.26 m water depth, H = 0.121 m, T = 1.560 s
15
700 705 710 715 720 725 730
Wav
e E
lev.
(m)
-0.2
-0.1
0
0.1
0.2
EXPERIMENT
4Subsea-kin
DNV-GL-ME-elv
DNV-GL-PF-elv
DTU-BEAM-kin
DTU-HAWC2-kin
IFE-kin
MARINTEK-elv
NREL-ME-elv1
NREL-ME-elv2
NREL-PF-elv1
NREL-PF-elv2
WavEC
700 705 710 715 720 725 730
Tota
l for
ce (N
)
-20
-10
0
10
20
30
Time (s)
700 705 710 715 720 725 730X-a
ccel
at 1
65 c
m (m
/s2
)
-1
-0.5
0
0.5
Test 7 – Irregular Wave – Shallower Water
16
Irregular Waves – Exceedance Probability Plots
Force (N)0 1 2 3 4 5 6 7 8 9 10
Pex
ceed
ance
10 -4
10 -3
10 -2
10 -1
10 0Test 3
Acceleration (m/s 2 )
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Pex
ceed
ance
10 -4
10 -3
10 -2
10 -1
10 0
Force (N)0 5 10 15 20 25 30
Pex
ceed
ance
10 -4
10 -3
10 -2
10 -1
10 0Test 7
Acceleration (m/s 2 )
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Pex
ceed
ance
10 -4
10 -3
10 -2
10 -1
10 0
DNV-GL-ME-elvDNV-GL-PF-elvDTU-BEAM-kinDTU-HAWC2DTU-HAWC2-PFDTU-HAWC2-kinEXPERIMENTIFE-kinIFP-PRI-elvMARINTEK-elvNREL-ME-elv1NREL-ME-elv2NREL-PF-elv1NTNU-LinPOLIMISWEUOUWMC-kin4Subsea-kinGEUC-IHC-kinWavEC
17
Conclusions • Higher-order wave theory important in capturing higher-order
components of hydrodynamic force o Extreme loads o Excitation of structural frequencies o Most important in shallow water
• Sloped seabed creates complex wave kinematics o Standard wave theories cannot account for slope o CFD-type analysis might be needed to create wave kinematics for non-
flat seabed conditions
• Majority of offshore wind modeling tools do not presently address breaking waves o Complex wave theories and CFD can accurately model steep waves
that will break o Need to model the impulsive load that a breaking wave will impart on
the structure o Some codes are seeking to include this
Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by Midwest Research Institute • Battelle
Thank You!
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
Amy Robertson +1 (303) 384 – 7157 Amy.Robertson@nrel.gov
Slide Number 1Co-Authors IEA Wind Tasks 23 and 30 (OC3/OC4/OC5)OC5 Project PhasesOC5 Phase IbTest Set-UpTests SimulatedSummary of Tools and Modeling ApproachCalibrationTest 1 – Regular Wave – Deeper Water - Force ResultsTest 6 – Regular Wave – Shallower Water - Force Results1st Peak Force Component2nd Peak Force Component3rd Peak Force Component Test 7 – Irregular Wave – Shallower WaterIrregular Waves – Exceedance Probability PlotsConclusionsThank You!