Numerical Investigation into the Effects of Layer and Accumulated Ice Floes on the Hydrodynamics Performance of the Damaged Ship

Due to the acceleration of global warming, the shrinkage of the compact ice-covered area allows the ice-going ship to transport through the Polar Sea Route. Collisions, naval operations, and fatigue would potentially cause hull deformation and damage. To better improve the safety of the polar ship in any extreme sea condition, this paper demonstrates the capability for the simulation of ship-ice-flooding interactions in still water. The main purpose is to investigate the effects of the ice floes and concentration on the flooding process and motion responses of the damaged ship. Computational Fluid Dynamics (CFD) is used to govern the fluid flow and motions of the damaged ship, while the Discrete Element Method (DEM) is applied to deal with the ice particle dynamics. Part injector and random injector are introduced to define the distribution of the ice floes. Three typical sea scenarios are simulated to perform the comparing analysis, including the open sea, the layer ice floes and the accumulated ice floes. Through the captured flooding process, the dynamic interactions between the ice floes and hull can be visualized. From the obtained simulation results, it can be found that the movement process of the ice floes in the damaged compartment can be divided into three stages, including the ice floes accumulation, the ice floes collapsing and the ice floes dispersion. Since the upright layer ice floes are more likely to be pushed underwater, the roll motion wouldn’t be affected much. However, the accumulated ice floes in close contact can provide efficient support for the hull, the roll amplitude of the damaged ship can be reduced. Moreover, for the accumulated ice floes scenario, the blocking effect near the damage opening is more obvious. In general, the proposed simulation method can provide a valuable reference for further investigations for the design of the polar ship or vessels that will operate on polar seas.