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transcript
Maneuverability of ships in ice: numerical simulation and
comparison with field measurements
Biao SuDepartment of Marine Technology, NTNU
May 28, 2013
Motivation
Local ice load
Global ice load
Ship’s performance
• Ice−hull interaction
• Local ice load
• Global ice load
• Ship’s performance
Outline
• Introduction
• Numerical modeling
• Gocal ice load
• Ship’s performance
• DP-ice capability
• Discussions
Global ice load
Ship’s peformance
Ice−hull interaction
(Riska, 2010)
• Crushing
• Bending
• Rotating
• Sliding
Ice breaking
Ice displacing
CrushingBending
Rotating
Sliding
Ship’s performance in ice• Ship’s performance in ice consists of ability to break ice and to
manoeuvre in ice – these capabilities are usually defined in ship’sfunctional specification.
• Specification values:
- Ship speed: 3.0 knots ahead in 1.0m thick ice and 3.0 knots astern in0.5 m thick ice
- Turning circle diameter: less than500 m in 0.5 m thick ice
Icebreaker Tor Viking II
Icebreaking capability• h-v cruve
v
h
The h-v curves determined from the full-scale tests of 4 icebreakers (Riska et al., 2001)
Icebreaking capability• h-v cruve
v
Ice resistance curves for different level ice thicknesses and the net thrust curve for USCGC Mackinaw (Riska, 2010)
21 2( ) 13 3net pull
ow ow
v vT v Tv v
∗ 11.4
∗ 19.4
(Lindqvist,1989)
Maneuverability• Turning circle diameter
Dt
An example of the recorded data of a full-scale turning circle test (Riska et al., 2001)
Numerical modeling• Valanto, 2001
• Liu et al., 2006
• Martio, 2007
• Nguyen et al., 2009
• Sawamura et al., 2010
• Lubbad & Løset, 2011
…Source: Valanto, 2007
Source: Lubbad & Løset, 2011
Izumiyama et al., 1992
• Su et al., 2010
Section A – A
A
A
Source: Riska, 2010
CrushingBending
Rotating
Sliding
Numerical modeling
Numerical modeling• Local ice load
• Global ice load
• Ship’s motion
Interation
Numerical modeling
Solve equations of motion
Updatehull nodes
Acceptable?
Detect the contact zones between ice and hull
Updatethe forces
Updateice nodes
No
Yes
Next time step
1 1 , 0( ) ( ) ( )k k kt t t F F F
1 1 , 1( ) ( )k k it t F F 1
1 12
6 3( ) ( )k k k kt tt t
x M + A B C F M + A a B b
1 1 , 1( ) ( )k k it t F F
1 , 1 1 , 1 , ( ) ( ) ( )k i k i k it t t F F F
Numerical modeling• Convergence test
- Global ice load- Discretization size of ice nodes: 1600, 800, 400, 200, 100, 50, 25 mm- Time step length: 0.032, 0.016, 0.008, 0.004, 0.002, 0.001, 0.0005 s
Numerical modeling• Computation time
- A 30-min icebreaking run- Discretization size of ice nodes: 1600, 800, 400, 200, 100, 50, 25 mm- Time step length: 0.032, 0.016, 0.008, 0.004, 0.002, 0.001, 0.0005 s
- Real-time simulation can be achieved by using a discretization size of 100 mm and a time step length of 0.01 s.
Case studies• MT Uikku
• MS Kemira
• S.A. Agulhas II
• Tor Viking II
• CIVArctic vessel
Local ice load
Global ice load and ship’s performance
Field tests Model tests
Case study – Tor Viking II• Comparison with field ice trials
Full-scale ice trial (Riska et al., 2001) Numerical simulation
Case study – Tor Viking II• Icebreaking pattern and icebreaking forces
0.6 m ice
0.5 m ice
Shoulder crushing
Case study – Tor Viking II• Icebreaking pattern and icebreaking forces
Time average: 356 kN
Time average: 389 kN
0.6 m ice
0.5 m ice
Crushing − bending
Continuous crushing
Case study – Tor Viking II• Ice resistance
A simulated time history of the ice forces encountered in surge direction (Tor Viking II, running straight ahead in 0.6 m thick ice)
A simulated time history of the ice forces encountered in surge direction (Tor Viking II, turning in 0.6 m thick ice)
Ice resistance: 938 kN
Ice resistance: 1129 kN
Straight going
Turning
Case study – Tor Viking II• The speed that the ship can attain in the ice (h-v cruve)
Shoulder crushing
Case study – Tor Viking II• Turning circle diameter
Case study – Tor Viking II• Simulated turning circle in 0.7 m thick ice:
Crushing
Bending
Case study – CIVArctic vessel• Comparison with ice model tests
Comparison of the icebreaking patterns, running ahead in 22 mm (0.53 m in full-scale) thick level ice
Comparison of the icebreaking patterns, running astern in 52 mm (1.26 m in full-scale) thick level ice
Case study – CIVArctic vessel• Double acting design
Lpp: 109.3 mBwl: 24 mDraught: 6.5 mDisp.: 12 000 t
- An optimum performance bow for open waters- Stern first when breaking ice
Source: Berg et al., 2011
Case study – CIVArctic vessel• The speed that the ship can attain in the ice (h-v cruve)
The speed that the vessel can attain, running ahead in the ice of increasing thickness (in
model-scale)
The speed that the vessel can attain, running astern in the ice of increasing thickness (in
model-scale)
Case study – CIVArctic vessel• Turning performance
A simulated turning circle in 19.7 mm (0.5 m in full-scale) level ice (Power 120%, propulsion azimuth 55°) with the corresponding velocity development time-series.
Time series of the forward speed recorded in the model test in 19.7 mm (0.5 m in full-scale) thick level ice (Power 120%, propulsion azimuth 55°, Source: Leiviskä, 2011)
Case study – CIVArctic vessel• Turning performance
Simulated turning circle in 19.7 mm (0.48 m in full-scale) thick level ice (Power 120%, propulsion
azimuth 35°, even keel)
Heeling angle: 1°
Heeling angle: 2°
Case study – CIVArctic vessel• Turning performance
Simulated turning circle in 19.7 mm (0.48 m in full-scale) thick level ice (Power 120%, propulsion
azimuth 35°, even keel)
Snow cover included
0
100
200
300
400
500
600
700
800
900
1000
0 20 40 60 80
Ice thickness [cm]
Turn
ing
diam
eter
[m]
Even keelHeeledRequired value
T=6.9 m
Full-scale turning tests with even keel and heeled(Riska et al., 2001)
Case study – CIVArctic vessel• Scaling of ice properties from model scale to full scale
Model-scale Scaling Full-scaleElastic modulus 17.26 MPa λ 416.62 MPaFlexural strength 21.92 kPa λ 0.53 MPaCrushing strength 43.84 kPa λ 1.06 MPaDensity 930 kg/m3 1 930 kg/m3
Poisson’s ratio 0.33 1 0.33Frictional coefficient 0.05 1 0.05
- Froude scaling
• Scaling of ice resistance and ship speed from model scale to full scale
MiPi RR 3 MP VV
Input
Output
Case study – CIVArctic vessel• Differences between model ice and sea ice
Model ice Sea iceElastic modulus 416.62 MPa 2.0 GPaFlexural strength 0.53 MPa 0.40 MPaCrushing strength 1.06 MPa 1.5 MPaDensity 930 kg/m3 900 kg/m3
Poisson’s ratio 0.33 0.33Frictional coefficient 0.05 0.10
The speed that the vessel can attain, running astern in the ice of increasing thickness
Input
Output
Ice properties from amission with KVSvalbard (Source:Lubbad & Løset, 2011)
Case study – CIVArctic vessel• DP-ice Capability analysis
Ice thickness
Ice drift angle
Ice drift speed
(Kjerstad et al., 2013)
- Towing simulations
- Descriptive ice load - Thruster allocation
Case study – CIVArctic vessel• DP-ice Capability analysis
- DP-ice capability plot parameterized by ice drift speed
Further studies• Large-area crushing
(Frederking, 1999)
(Tan et al., 2013)
Pressure-area relationship
Further studies• Fluid-ice interaction during ice bending
(Sawamura et al., 2011)
Further studies• Rotating and sliding of broken ice pieces
Rotating
Sliding
(Zhou et al., 2012)
2 2
1 10.7 cos cos 1 9.42 tan 4tan sin tans i
B T T B vR gh B T L TB T gL
(Lindqvist,1989)
Further studies• 6-DOF ship’s motions in level ice
3-DOF model 6-DOF model
(Tan et al., 2012)
Further studies• Stationkeeping of a moored ship in level ice
(Zhou et al., 2012)
Summary
• Numerical modeling of ice−hull interaction
• Global ice load and ship’s performance
• Full-scale comparison
• Model-scale comparion
• Further studies
References[1] Berg, T.E., Berge, B.O., Hӓnninen, S., Suojanen, R.A. and Borgen, H., 2011. Design considerations for an Arctic
intervention vessel. Proc. Arctic Technology Conference 2011, Houston, Texas, USA.
[2] Frederking, R., 1999. The local pressure–area relation in ship impact with ice. Proceedings of 15th InternationalConference on Port and Ocean Engineering under Arctic Conditions (POAC), Helsinki, Finland.
[3] Izumiyama, K., Kitagawa, H., Koyama, K. and Uto, S., 1992. A numerical simulation of ice-cone interaction.Proceedings of 11st International Symposium on Ice (IAHR), Banff, Alberta, Canada.
[4] Kjerstad, Ø., Skjetne, R., and Berge, B., 2013. Constrained Nullspace-based Thrust Allocation for Heading PrioritizedStationkeeping of Offshore Vessels in Ice. Accepted by 21st International Conference on Port and Ocean Engineeringunder Arctic Conditions (POAC), Espoo, Finland.
[5] Leiviskä, T., 2011. Performance and DP tests in ice with CIV ARCTIC vessel. AARC Report A-454, September 2011,Aker Arctic.
[6] Lindqvist, G., 1989. A straightforward method for calculation of ice resistance of ships. Proceedings of 10th
International Conference on Port and Ocean Engineering under Arctic Conditions (POAC), Lulea, Sweden.
[7] Liu, J.C., Lau, M. and Williams, F.M., 2006. Mathematical modeling of ice–hull interaction for ship maneuvering in icesimulations. Proceedings of 7th International Conference and Exhibition on Performance of Ships and Structures inIce (ICETECH), Banff, Alberta, Canada.
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Laboratory, Helsinki University of Technology, Finland.
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[11] Riska, K., Leiviskä, T., Nyman, T., Fransson, L., Lehtonen, J., Eronen, H. and Backman, A., 2001. Ice performance ofthe Swedish multi-purpose icebreaker Tor Viking II. Proceedings of 16th International Conference on Port and OceanEngineering under Arctic Conditions (POAC), Ottawa, Canada.
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[13] Sawamura, J., Tsuchiya, H., Tachibana, T. and Osawa, N., 2010. Numerical modeling for ship maneuvering in levelice. Proceedings of 20th International Symposium on Ice (IAHR), Lahti, Finland.
[14] Sawamura, J., Kikuzawa, R., Tachibana, T. and Kunigita, M., 2011. Numerical investigation of the ice force distributionaround the ship hull in level ice. Proceedings of 21st International Conference on Port and Ocean Engineering underArctic Conditions (POAC), Montreal, Canada.
[15] Tan X., Su, B., Riska, K., and Moan, T., 2012. The effect of the heave, pitch and roll motions to ice performance ofships. Proceedings of 21st IAHR International Symposium on Ice, Dalian, China.
[16] Tan X., Su, B., Riska, K., and Moan, T., 2013. The effect of icebreaking pattern and pressure-area relation on ship’sperformance in level ice. Accepted by Cold Regions Science and Technology.
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Regions Science and Technology, Vol. 60, pp. 177-188.
[18] Su, B., 2011. Numerical predictions of global and local ice loads on ships. Ph.D. thesis, Norwegian University ofScience and Technology, Trondheim, Norway.
[19] Su, B., Riska, K., Moan, T. and Berg, T.E., 2012a. Full-scale and model-scale simulations of a double actingintervention vessel operating in level ice. Proceedings of 21st IAHR International Symposium on Ice, Dalian, China.
[20] Su, B., 2012b. Full-scale and model scale simulations of the level ice performance of CIVARCTIC Vessel. Report No.530529, MARINTEK, Trondheim, Norway.
[21] Valanto, P., 2001. The resistance of ships in level ice. Transactions of Society of Naval Architects and MarineEngineers (SNAME), Vol. 109, pp. 53-83.
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[23] Zhou, L., 2012. Numerical and experimental investigation of stationkeeping in level ice. Ph.D. thesis, NorwegianUniversity of Science and Technology, Trondheim, Norway.
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