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DYNAMIC POSITIONING CONFERENCEOctober 9-10, 2012
ARCTIC/ICE OPERATIONS SESSION
Numerical Simulation of Dynamic Positioning in Ice
Ivan Metrikin and Sveinung LøsetNorwegian University of Science and Technology (NTNU)
Nils Albert JenssenKongsberg Maritime
S fi K k iSofien KerkeniDCNS Research/Sirehna
Numerical Simulation of Dynamic Positioning in Ice
Ivan Metrikin and Sveinung LøsetDepartment of Civil and Transport Engineering
Nils Albert JenssenKongsberg Maritime
Sofien KerkeniDCNS Research/Sirehna
A ti /I O ti
Norwegian University of Science and TechnologyTrondheim, Norway
Kongsberg, Norway Nantes, France
Arctic/Ice OperationsDynamic Positioning Conference9-10 Oct 2012 Houston, TX, USA
Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
10 Oct 2012 Ivan Metrikin et al. 2/31
– Fully Coupled Numerical DP Simulations, Experimental Validation
Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
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– Fully Coupled Numerical DP Simulations, Experimental Validation
Fields of Application• Ice loads on ships • DP vessel concepts
10 Oct 2012 Ivan Metrikin et al. 4/31http://2.bp.blogspot.com/-SgnBviPQDPA/Tz_-jDm-r6I/AAAAAAAAC18/Ne21KAAF0hg/s1600/ice_breaker.jpg Screenshots from the DelftShip software, Parent 40 icebreaker model
Fields of Application• DP control schemes • Training simulators
10 Oct 2012 Ivan Metrikin et al. 5/31http://www.saltwaterpr.com/Content/Story/2010/Large/KM_Offshore_SIM_01_m.jpg www.smsc.no
Fields of Application• Multi-vessel operations • Risk assessment
10 Oct 2012 Ivan Metrikin et al. 6/31Rohlén, 2009 http://i.thestar.com/images/bf/16/f83e1e124d52bc368d949b6fe2cc.jpeg
Fields of Application• Integrated systems • Scientific research
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Illustration: Bjarne Stenberg
Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
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– Fully Coupled Numerical DP Simulations, Experimental Validation
Physical Ice Environment
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Ice Management
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Moran et al., 2006 Illustration: Joakim Haugen
Managed Ice• Discrete-continuum material
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Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
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– Fully Coupled Numerical DP Simulations, Experimental Validation
Empirical Models
Sh d i f th i f tIce VesselShapes and sizes of the ice features
Ice and water densitiesIce material strengthIce floe size distributionI t ti
Shape and size of the hullMass and inertia tensorFriction properties of the hullH d d i f th l
Vessel
Ice concentrationIce confinementHydrodynamics of the ice pieces (e.g. added mass)Presence of snow coverF i ti
Hydrodynamics of the vesselFroude numberPropulsion
http://icyseas.files.wordpress.com/2012/06/rimg0129.jpg
Friction
I l d F( )
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Ice loads = F(…)
Statistical ApproachIce loads = F(ice, vessel) = const
Monte Carlo simulation
Gauss Poisson Weibull
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Ice loads = F(ice, vessel) = F(t)
Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
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– Fully Coupled Numerical DP Simulations, Experimental Validation
Experimental Data Series Methods
I fi ld
3 DOF
Ice field• Dyn. inertia• Damping
• Thrust
Damping
• Ice loads• Drag
• Coriolis• Centrifugal• RPM
• Azimuth
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• Inertia• Azimuth
Open-water DP vs. ice-adapted DP
-20
0
20
[m]
Pos North
-20
-10
0
10
[m]
Pos North
0 2000 4000 6000 8000 10000
20
[sec]
0
20Pos East
0 2000 4000 6000 8000 10000-30
[sec]
0
Pos East
Recorded
0 2000 4000 6000 8000 10000-40
-20
0
[m]
[sec]0 2000 4000 6000 8000 10000
-40
-20[m]
[sec]
SimulatedSetpoints
[ ]
160
170
180
190
[deg
]
Heading[sec]
180
190
[deg
]
Heading
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0 2000 4000 6000 8000 10000150
160
[sec]0 2000 4000 6000 8000 10000
170
[sec]Full-scale values
Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
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– Fully Coupled Numerical DP Simulations, Experimental Validation
Physically Based Modeling• Fundamental laws of physics• High fidelityHigh fidelity• Real system dynamics
Millan and Wang 2011
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Millan and Wang, 2011
Zhan and Molyneux, 2012
Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
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– Fully Coupled Numerical DP Simulations, Experimental Validation
Structure of the ModelVoortex phhysics e
WindWaves
engine
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Waves
The DP VesselLength between perpendiculars 184.00 mBreadth, moulded 41.33 mDesign draught 12 00 mDesign draught 12.00 mDraught at aft perpendicular 12.00 mDraught at fwd. perpendicular 12.00 mDisplacement volume 68457 m³Centre of gravity from aft perp. 95.34 mBlock coefficient 0.75
- 3 azimuths bow3 azimuths bow
Propulsion: 5.4 MNCAD model
2956 vertices5908 faces
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Illustration: Statoil - 3 azimuths stern5908 faces
Ice Conditions
Assumptions
- 6 DOF RBs- Unbreakable- Undeformable- No brash ice- No added mass- No hydrodynamic damping- No ventilation
10 Oct 2012 Ivan Metrikin et al. 23/31Courtesy HSVA
Contents• Fields of Application• Physical Ice Environment• Ice Loads Modeling for Numerical DP Simulations
– Empirical and Statistical Models– Experimental Data Series Methods– Physically Based Modeling
• NTNU Numerical Model– Model Description
F ll C l d N i l DP Si l ti E i t l V lid ti
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– Fully Coupled Numerical DP Simulations, Experimental Validation
DP SimulationsS l f t 30Scale factor = 30
Ice drift = 0.5 ktsship moves p
through the ice
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The same DP control system and the same tuning as in the ice basin
Ice Drift Angle = 0°
Ice tankNumeric
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Ice Drift Angle = 5°
Ice tankNumeric
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Ice Drift Angle = 10°
Ice tankNumeric
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Conclusions
To the authors’ knowledge, this is the first publication p
of a fully coupled numerical simulation of DP in managed ice performedin managed ice performed
at such fidelity level
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ConclusionsEmpirical and
statistical modelsExperimental data
series methods Physically based modeling
Numerical Reliable for certain • High fidelityStrengths Numerical efficiency
Reliable for certainconditions
• High fidelity• Real system dynamics
P ibl• Can be difficult to
t dWeaknesses Possible oversimplification
extend• Uncoupled ice-
vessel dynamics
Computationally demanding
Recommended usage
Initial testing of the DP controllers
Tuning the DP systems to a
particular set of
• Numerical performance assessments
• Robustness analysesD t il d t ti f th DP
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usage DP controllers particular set of conditions • Detailed testing of the DP
control systems
AcknowledgementsThe authors would like to thank the Research Council of Norway (RCN) for the financial support of the MARTEC ERA-NET project “DYPIC - Dynamic positioning in ice covered waters” (RCN Project No 196897) and the Arcticpositioning in ice covered waters (RCN Project No. 196897) and the Arctic DP project (RCN Project No. 199567/I40). The authors would also like to thank the Ministry of Ecology, Sustainable Development, Transport and Housing (France) and the Federal Ministry of Economics and Technology (G ) f f f C(Germany) for their financial support of the MARTEC ERA-NET project “DYPIC–Dynamic positioning in ice covered waters.” Additionally, the authors would like to thank their industry sponsor, Statoil ASA, their project partners Det Norske Veritas and Hamburg Ship Model Basin and thepartners, Det Norske Veritas and Hamburg Ship Model Basin, and the authors’ affiliated companies for the permission to publish this paper. Finally, the authors are thankful to Mr. Dmitry Sapelnikov (NTNU) for his efforts in implementing the NTNU numerical simulator
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Full reference list can be found in the paper
