Seakeeping Performance And Stability Study Of Trimaran Small Waterplane Area Center Hull By Using CFD Technology

In recent years,with the development of marine resources and marine transportation industry,people put forward higher requirements for various performances of ships,including economy,safety,comfort,specifically including high-speed performance,seakeeping performance,stability,sinking resistance,which have become more and more important for people to consideration.The potential of traditional ship type is limited in these aspects,and cannot meet the needs of modern transportation industry.Driven by this demand,as a new way of thinking,the development of new ship comes into being with the progress of science and technology.As a high-performance ship,trimaran has a wide deck area,good stability,less resistance and better wave resistance.Compared with traditional trimaran,trimaran small waterplane area center hull(Triswach)has larger potential and greatly reduces the waterline area.Therefore,the law of wave resistance and stability of ordinary trimaran cannot be fully applied to Triswach.The wave resistance and stability of Triswach need to be studied.Because of the model test needed long period,high cost and strict environmental requirements,it is difficult to test and analyze all schemes STARCCM+ + platform is used to simulate the viscous flow around the hull.Considering the influence of grid setting and flow field model selection,the feasibility and reliability of the seakeeping calculation of STAR-CCM+ platform are verified firstly;then the seakeeping change law of Triswach is studied under different side body positions under a series of Froude numbers.Since it is the first time to simulate the restoring force arm curve of Triswach,the wave flow field in STAR-CCM+ by using the method of forced heeling experiment,firstly verify that the condition setting and research method of the flow field can be applied to its stability study,and then according to the performance of the stability arm under different side body layout schemes at different speeds,the influence of the side body layout on its stability is obtained.The details are as follows:(1)In this paper,the basic method of CFD analysis of viscous flow field,turbulence model selection and continuity equation,mesh generation,initial and boundary conditions,VOF free surface capture principle are introduced in detail,which provides theoretical support for the follow-up study of seakeeping and wave stability.(2)Seakeeping analysis of Triswach under the condition of head wave is carried out.Firstly,three longitudinal positions and two transverse positions and all four different side body positions are arranged,with the effectiveness of STAR-CCM+ software in the calculation of seakeeping performance of Triswach is verified,then the amplitude of response to pitching and heave when the side body is in different positions is analyzed,and the influence of different side body positions on seakeeping performance of Triswach under different Froude numbers is obtained,which could provide suggestion of seakeeping performance for the design.(3)For the analysis of the wave stability of the Triswach sailing along the waves,the paper introduces the ship type schemes of various side body positions.The restoring force arm under the different speed with three Froude numbers of = 0.234,0.494 and 0.701 are calculated respectively.The laws of the side body layout and the speed are obtained which provide useful suggestion on the stability of design.