Design Optimization And Application Of Ship Stern Flaps

Ship is playing an important role in the transport of energy sources,as the carrier of realizing the value of shipping market,it is also heavy energy-dependent.And ship energy-saving has been involved in each manufacturing process.However,since the depressed shipping market,the quantity of new ships is decreasing year by year,and the research on resistance reduction and energy saving has become a hot spot.At present,many resistance reduction methods are applied to ships,such as rib resistance reduction method,air curtain resistance reduction method,bubble resistance reduction method and polymer additive resistance reduction method,etc.Among them,the technical difficulties vary,and resistance reduction and energy saving are achieved by changing the ship's sailing state,adding material or appendage structure to the hull.In the paper,by reference of the common resistance-reducing appendage of scooter,stern flap,a series of studies have been made on which and several forms have been put forward.Based on the widely used numerical simulation technology in resistance prediction,numerical simulation analysis has been carried out by the CFD commercial software,STAR-CCM+.Firstly,the feasibility and accuracy of the calculation software and related methods are verified by the numerical simulation of KCS standard ship form.Then the influence of different forms of stern flaps on ship resistance performance under different scale parameters has been investigated.Then,the fireboat,which has higher requirement for rapidity,is selected as the installation carrier of flap.In the process of numerical simulation,the shape of Wave-Breaker is optimized,and the relevant scale parameters(including length,width and angle)of the optimal shape are optimized and analyzed to obtain the stern flap with the highest resistance reduction rate.The resistance reduction mechanism and effect are analyzed in detail.Besides,the effect of the combination of the optimal flap and twin skeg on resistance performance is briefly explored,and resistance reduction is achieved well.Finally,the resistance of ships during navigation is predicted by STAR-CCM+.In the process of studying the effect of stern flaps,the regularity of the resistance performance of ships with different types of stern flaps is obtained.This regularity provides general guidance and reference for the resistance prediction of medium and high speed ships with stern flaps,and has higher value in engineering application.