Simulating Narrow Channel Effect on Surge Motion of a Ship in a Virtual Environment Chethaka Uduwarage Chamath Keppitiyagama Rexy Rosa Nihal Kodikara Damitha Sandaruwan Chathura Gunasekara ICTer2012-13 December, 2012
Outline Introduction Key Literature Reference Research Question Methods Results Discussion/Conclusion Future Works References Q&A
Introduction Enhancement of real-time computer based ship simulation in narrow channels, which can be used for ship navigational trainings. Present an analysis of observations and findings on the narrow channel resistance on surge motion of a ship
Introduction Resistance force effect in narrow channels is calculated considering Channel Width Channel Depth
simulator Capabilities to Navigation Trainings in Narrow Channels Shallow-water flows past slender bodies by E.O.Tuck Researched on real world narrow channels Results showed satisfactory agreement with model experiments. Derived formulas for wave resistance, vertical forces, and pitching moments. Theoretically narrow channel equations are true for real world ship navigations.
Review Cont Ship squat predictions for ship/tow simulator by M. Briggs Have done real world narrow channel experiments. Simulation can be done for three main types of entrance channels, Unrestricted or unbounded (U) Restricted or bounded (R) Canal (C) Existing squat formulas are not accurate for larger and deeper draft vessels.
Review Cont Assessment of maneuvering performance of large tankers in restricted waterways by K. Sario z, E. Narli Complex hydrodynamic phenomenon that is difficult to predict in a form useful in real-time simulations. Complicated by the presence of channel boundaries and depth effects. The ship ship interaction model is a theoretical approach with empirical corrections based on model test results.
Review Cont Channel Design and Vessel Maneuverability by William O. Gray Ship simulation is used to test or verify a conceptual Simulator is used as a navigation channel design tool because it is giving accurate results for designing navigation channels. It does not support real time simulations. Therefore it can not be used for real time navigation trainings in narrow channels.
Review Cont Commercial ship simulations systems Expensive and closed systems ARI Navigation simulator Transas Virtual Sailor Ship Simulator Extremes
Review Cont Principles of Naval Architecture by Edward Lewis's Explains frictional and wave making resistance factors which affect real world ships in narrow channels. There mathematical model equation simply explains which narrow channel characteristics and ship properties affect the motion of the ship in a narrow channel.
Review Cont Vidusayura Has its own physics model and algorithms to calculate real time ship motions. Algorithms for narrow channels are not implemented as suitable for real time ship motion and the physics model. Ship movements are calculated, considering the ship as a box and hull design have to be considerd.
Summary of the Review
Why Vidusayura? Has an accepted ship motion prediction algorithm using less number of characteristics which supports real time predictions. Algorithms for narrow channels are not implemented as suitable for real time ship motion and the physics model. As one of the research objectives, prediction algorithms for narrow channels will be implemented into this Vidusayura Simulator.
Methodology and Approach RESISTANCE FORCE ON SURGE MOTION Because of narrow channel properties, there is a resistance force on surge motion of a ship and it is controlling the velocity of the ship Blockage factor =
Methodology and Approach Real world resistance force equation on surge motion of a ship [according to Principles of Naval Architecture ] A x R H -- maximum submerged cross-sectional area of a hull -- hydraulic radius of the vessel. Where, bc-- channel width hc-- channel depth p -- Vessel s wetted surface perimeter / wetted girth of hull at this section
Methodology and Approach Surge motion of a ship in Vidusayura Drag force due to combined yaw and sway motion become 0 in a straight course Surge motion with narrow channel resistance Mü = T e - X u u u u - (M + X vr )vr R 0 Independent from ship motion
Results Changing of narrow channel properties, affecting to ship navigation (For a constant engine force) Ship Breadth 25m Draft 10m Length - 100m
Results Changing of narrow channel properties, affecting on smaller ships (For a constant engine force) Ship Breadth 5m Draft 2m Length - 20m
Conclutions Linear velocity drops when the channel width or channel depth is decreasing for large and small ships Resistance in linear velocity can be neglected if both channel width and depth become larger values (>10000m)
Future Works Bank or wall effect, surface and submerged channel effec In proximity of the bank: Velocity increases Static pressure drops Water level drops Suction force that draws the ship closer to the bank
VERIFY NARROW CHANNEL TRAININGS Follow the rules in DNV Navigator and STCW http://www.dnv.com/services/software/products /DNVNavigatorServices/index.asp http://www.stcw.org/ Verify navigation results with standard numerical charts. User feedbacks from Naval Maritime Academy in Sri Lanka Navy
References WAVES GENERATED BY TWO OR MORE SHIPS IN A CHANNEL. C. F. N. Maria Francisca do Nascimento, Geraldo de Freitas Maciel. 2010. Proceedings of the International Conference on Coastal Engineering. p. 11. J. W. J. Raymond, A. Serway.Principles of Physics: A Calculus-Based Text. 2005. Vol. 1. ISBN 0534491448. What Lies Beneath the Surface. Hardy, G. 2007. Ocean Technology 2007. Vol. 2. 4. Channel Design and Vessel Maneuverability - Next Steps WHEN SHIPS GET TOO BIG FOR THEIR DITCHES - GRAY. J. W. William O. Gray, Alan Blume, and Alexander C. Landsburg. 2001. International workshop on Channel Design & Vessel Maneuverability. Ship Squat Predictions for Ship/Tow Simulator. Briggs, M. J. Vicksburg, MS : U.S. Army Engineer Research and Development Center, 2006. Coastal and Hydraulics Engineering Technical Note CHETN-I-72.
References Assessment of manoeuvring performance of large tankers in restricted waterways: a realtime simulation approach. Sario z, E. N. K. 2003. Ocean Engineering 30 (2003). ISBN 1535 1551. ARI. Navigation - Full Mission Ship Maneuvering Simulator. ARI Simulations. [Online] 2011. [Cited: 6 8, 2012.] http://www.arisimulation.com/navigation%20- %20Full%20Mission%20Ship%20Maneuvering%20Simulator.asp Transas. Navigational Simulators. Transas. [Online] 2012. [Cited: 6 8, 2012.] http://www.transas.com/products/simulators/sim_products/navigational/. Sailor, Virtual. Virtual Sailor Features. Virtual Sailor. [Online] 2008. [Cited: 6 8, 2012.] http://www.hangsim.com/vs/. Ship Simulator Wikipedia. Ship Simulator. Wikipedia. [Online] 2010. [Cited: 6 8, 2012.] http://en.wikipedia.org/wiki/ship_simulator.
References Realtime Ship Motion Prediction System. D.Sandaruwan, N.Kodikara, C.Keppitiyagama, R.Rosa. 2010. Computer Games, Multimedia and Allied Technology-CGAT 2010. ISBN 978-981-08-3165-3. Lewis, Edward V.Principles of Naval Architecture. Jersey City : The society of Naval Architects and Marine Engineers, 1988. Vol. 2. House, D. J.Seamanship Techniques: Shipboard and Marine Operations. 2. 2001. pp. 241-242. Vol. 2. ISBN 0 7506 5231 4. A six degree of freedomship simulation system for maritime education. D Sadaruwan, C Keppetiyagama. 2010, ICTER. Fincham, Michael W. Chesapeake Quarterly. Big Boats, Narrow Channels. July 2005, Vol. 4, 2.
References oleh, Diposkan. Ship Handling Effects Of Banks, Channels, and Shallow Water. Ship Handling. [Online] September 23, 2009. http://onevoyage.blogspot.com/2009/09/ship-handling-effects-of-banks-channels.html. Dvora class fast patrol boat. Wikipedia. [Online] January 2012. http://en.wikipedia.org/wiki/dvora_class_fast_patrol_boat. Simon, Donald C.Wave Patterns. Steel Navy. [Online] Wall Street Journal, April 27, 2004. http://www.steelnavy.com/wavepatterns.htm. Ship Entry into a Lock. Chen, Xue-Nong. Hiroshima : s.n., 2001. Water Waves and Floating Bodies. Analysis of Wave Making Resistance and Optimizaion of Canting Keel Bulbs. Karsten Hochkirch, Claudio Fassardi. Maryland : Chesapeake Sailing Yacht Symposium, 2007. From water entry to lock entry. Chen, Xue-nong. Shanghai : s.n., 2010. 9th International Conference on Hydrodynamics.
Q & A