The ice resistance on a ship hull affects the safety of the hull structure and the ship maneuvering performance in icecovered regions.In this paper,the discrete element method(DEM)is adopted to simulate the interactio...The ice resistance on a ship hull affects the safety of the hull structure and the ship maneuvering performance in icecovered regions.In this paper,the discrete element method(DEM)is adopted to simulate the interaction between level ice and ship hull.The level ice is modeled with 3D bonded spherical elements considering the buoyancy and drag force of the water.The parallel bonding approach and the de-bonding criterion are adopted to model the freezing and breakage of level ice.The ship hull is constructed with rigid triangle elements.To improve computational efficiency,the GPU-based parallel computational algorithm was developed for the DEM simulations.During the interaction between the ship hull and level ice,the ice cover is broken into small blocks when the interparticle stress approaches the bonding strength.The global ice resistance on the hull is calculated through the contacts between ice elements and hull elements during the navigation process.The influences of the ice thickness and navigation speed on the dynamic ice force are analyzed considering the breakage mechanism of ice cover.The Lindqvist and Riska formulas for the determination of ice resistance on ship hull are employed to validate the DEM simulation.The comparison of results of DEM,Lindqvist,and Riska formula show that the DEM result is between those the Lindqvist formula and Riska formula.Therefore the proposed DEM is an effective approach to determine the ice resistance on the ship hull.This work can be aided in the hull structure design and the navigation operation in ice-covered fields.展开更多
The Arctic is rapidly transforming into a navigable ocean because of global warming.The retreat of ice extent and widened marginal ice zone(MIZ)in the Arctic made it possible for non-icebreaking commercial vessels to ...The Arctic is rapidly transforming into a navigable ocean because of global warming.The retreat of ice extent and widened marginal ice zone(MIZ)in the Arctic made it possible for non-icebreaking commercial vessels to sail into Arctic waters where ice floes of various concentrations and thicknesses exist.The main objective of this work is to estimate the performance of a non-icebreaking cargo ship that sails in the Arctic marginal ice zone.Different numerical approaches are utilized to calculate ice-induced resistance and compared with those proposed in empirical formulas.The comparison shows that the resistances predicted by the two numerical tools differ obviously and are in general smaller in comparison with the ones calculated from the empirical formulas under lower ice concentrations.The total resistances are further calculated to predict the required propulsion powers for the case study vessel to enable navigation under severe ice conditions.This work highlights the significance of developing new and more sophisticated tools for estimation of ship’s ice performance in MIZ,which is the prerequisite to enable non-icebreaking cargo fleet to utilize the Arctic shipping lane.展开更多
基金This study is financially supported by the National Key Research and Development Program of China(Grant Nos.2017YFE0111400 and 2016YCF1401505)the National Natural Science Foundation of China(Grant Nos.41576179 and 51639004)the China Postdoctoral Science Foundation(Grant No.2020M670746).
文摘The ice resistance on a ship hull affects the safety of the hull structure and the ship maneuvering performance in icecovered regions.In this paper,the discrete element method(DEM)is adopted to simulate the interaction between level ice and ship hull.The level ice is modeled with 3D bonded spherical elements considering the buoyancy and drag force of the water.The parallel bonding approach and the de-bonding criterion are adopted to model the freezing and breakage of level ice.The ship hull is constructed with rigid triangle elements.To improve computational efficiency,the GPU-based parallel computational algorithm was developed for the DEM simulations.During the interaction between the ship hull and level ice,the ice cover is broken into small blocks when the interparticle stress approaches the bonding strength.The global ice resistance on the hull is calculated through the contacts between ice elements and hull elements during the navigation process.The influences of the ice thickness and navigation speed on the dynamic ice force are analyzed considering the breakage mechanism of ice cover.The Lindqvist and Riska formulas for the determination of ice resistance on ship hull are employed to validate the DEM simulation.The comparison of results of DEM,Lindqvist,and Riska formula show that the DEM result is between those the Lindqvist formula and Riska formula.Therefore the proposed DEM is an effective approach to determine the ice resistance on the ship hull.This work can be aided in the hull structure design and the navigation operation in ice-covered fields.
基金supported by the National Natural Science Foundation of China(Grant No.2017YFE0111400).
文摘The Arctic is rapidly transforming into a navigable ocean because of global warming.The retreat of ice extent and widened marginal ice zone(MIZ)in the Arctic made it possible for non-icebreaking commercial vessels to sail into Arctic waters where ice floes of various concentrations and thicknesses exist.The main objective of this work is to estimate the performance of a non-icebreaking cargo ship that sails in the Arctic marginal ice zone.Different numerical approaches are utilized to calculate ice-induced resistance and compared with those proposed in empirical formulas.The comparison shows that the resistances predicted by the two numerical tools differ obviously and are in general smaller in comparison with the ones calculated from the empirical formulas under lower ice concentrations.The total resistances are further calculated to predict the required propulsion powers for the case study vessel to enable navigation under severe ice conditions.This work highlights the significance of developing new and more sophisticated tools for estimation of ship’s ice performance in MIZ,which is the prerequisite to enable non-icebreaking cargo fleet to utilize the Arctic shipping lane.
