Numerical Study Of The Influence Of New Drag Reduction Appendages On Resistance Performance Of High Speed Ships

With the continuous development of the world economy,the demand for ships in the trade of various countries is getting higher and higher.However,the world’s energy is also facing a serious shortage,so the application of ship energy-saving accessories is inevitable.The energy-saving appendage of a ship is a component installed in the bow,stern or ship to improve the flow field around the ship without changing the existing ship type.The ship appendages usually have the characteristics of simple structure,small size,convenient installation,and can improve the resistance performance and maneuverability of ships.They have high application value for high-speed ships.With the continuous development of CFD technology,the prediction of ship hydrodynamic performance by CFD numerical simulation method is becoming more and more popular in the shipping industry.Based on STAR-CCM+ simulation software,this paper carries out a numerical study on adding drag reduction appendages to Model5 b numerical model and proposes a new type of resistance reduction appendages with excellent resistance reduction effect.The main research contents of this paper include:(1)The effect of the combination of drag-reducing appendages on the resistance performance of high-speed ships is studied.In this part,based on the commonly used stern wave suppression plate installed in high-speed ships,numerical simulation is carried out for the combination of stern wave suppression plate,baffle plate and diversion groove.The influence of parameters of stern pressure wave plate,interceptor and diversion groove on the resistance performance of high-speed ships is further analyzed.Finally,a new type of resistance reduction appendage with better resistance reduction performance is obtained by combining the simulation results.(2)The ship model with new resistance reduction appendages is selected as the main research object.And the resistance in the still water is simulated by STAR-CCM+simulation software.In this part,the hydrostatic resistance performance of Model5 b naked ship,ship with conventional plate and ship with new resistance reduction appendages at different speeds is calculated successively.And by comparing the resistance of the three elements under the same working condition,a conclusion is drawn that the new resistance reduction appendages have better resistance reduction performance.Finally,according to the mechanism of resistance reduction of the composite appendages,the effect of the resistance reduction appendages on the residual resistance of the ship was analyzed.(3)CFD numerical simulation software and overlapping grid method are used to simulate the ship model with new resistance reduction appendages sailing in regular waves.Five groups of wave generation and propagation at different wavelengths were successfully simulated by establishing a three-dimensional numerical wave tank,using the direct wave-making method at the entrance and the artificial damping Wave-elimination technology.The resistance performance and motion response of the bare Model5 b ship,the conventional slab ship and the new resistance reduction appendage ship at different wavelengths and speeds were calculated respectively.Finally,the resistance performance,heave and pitch of naked ship,ship with conventional plate and ship with new resistance reduction appendages under the same working condition are compared,which further verifies that the new resistance reduction appendages not only has better resistance reduction effect,but also has the effect of improving the pitch of ship.