Study On The Damaged Stability Of Ships Sailing In The Arctic

At present,the increasing global warming has led to the accelerated melting of Arctic sea ice,and polar navigation has become a reality.The Arctic channel can greatly shorten the route from Asia to Europe or North America,save navigation time and reduce transportation costs.Therefore,the number of merchant ships choosing the Arctic channel is increasing.However,due to the harsh environment in the Arctic region,the ship may collide with the iceberg due to the obstruction of the dense fog line of sight or improper operation in the navigation process,resulting in the damage of the hull surface and the seawater into the cabin,resulting in changes in the floating state and stability of the ship.In addition,the influence of ice accretion on ship hull and ice floes on the sea surface can’t be ignored during polar navigation.At present,there are few studies on damaged ship considering the influence of ice accretion and ice floes on the sea surface during navigation,so it is great significant to carry out the research on the damaged stability of ships sailing in the Arctic.In this paper,a multi-purpose ship is taken as the research object.Firstly,MATLAB program is used to draw the ship stability curve and solve floating state.Assuming that a variety of damaged ship are solved respectively,the stability curve is compared and analyzed,and the influence of ship damage on the stability curve is obtained.Secondly,the STAR-CCM+ software is used to numerically simulate the typical flooding situation.The instantaneous flooding state of the ship was observed,and the curves of the roll,pitch,heave motion and mass flow at the breach during the whole flooding process were obtained.The results show that the rolling angle of the ship increases continuously in the initial stage.With the decrease of the inlet velocity and the influence of the rolling damping,the amplitude of the rolling angle of the ship decreases continuously,and gradually enters the quasi-static stage until the ship is stable at the equilibrium position.The reliability of the program and numerical simulation is verified by comparing the results of the ship equilibrium state.Thirdly,MATLAB program is used to predict the total amount of ice accretion on the hull.Through the input of ship type parameters and environmental parameters,the simplification of the ship model,the amount of droplet droplets on the grid,the ice accretion coefficient,weight and gravity center are calculated.The reliability of the icing calculation program is verified by comparing the calculation results with the reference range in the 2008 IS code.The influence trend of different environmental parameters on the ice accretion of ships is analyzed.The results show that the larger the wind speed,the larger the ship speed and the lower the ambient temperature are,the more the ice accretion on the hull surface is,and the ice accretion is mainly concentrated in the bow of the ship.The numerical simulation of the flooding process of the ship after ice accretion is carried out.The results show that the roll angle of the equilibrium position of the ship after ice accretion is larger,the pitch angle is smaller and the heave is larger.Finally,the STAR-CCM+ software is used to simulate the navigation process of ship in ice floes,and the reliability of the method is verified by comparing it with experimental data.On this basis,the flooding during the navigation of the ship in ice floes is simulated.The results show that at the initial stage of flooding,the ship rolls violently,causing the change of the flow field near the ship,and ice floes gather behind the stern.The ice load makes the maximum roll angle of the ship increase greatly.At the same time,compared with the static water,the motion time history curve of flooding during the ship sailing in ice floes fluctuates with different amplitudes near the equilibrium position.