Optimization Scheme Research On The Side Hull Configuration And Position Of High Speed Trimaran Based On Orthogonal Design Method

Modern high-speed trimarans are widely researched because of its characteristics such as good rapidity, ship stability, excellent resistance properties, the spacious exposed deck, and so on. The existence of the side hull raises the ship’s stability, at the same time increases the useful deck area of the connection between the side hull and the main body. Compared with the mono-hull ship, trimaran has smaller side hull, lower cost, qualitatively improved performance, especially a unique advantage in the aspect of reducing the wave-making resistance. Frigate, one kind of high-speed trimaran, of which the length coefficient of the main body is larger by 20% than similar mono-hull ship, width reduced by 25%, has more slender waterplane which is helpful to reduce wave resistance. Side hull’s molded lines and the arrangement of side hull’s position have a great influence on the wave pattern generated by the main hull. The reasonable design of side hull’s molded lines and arrangement of side hull’s position can eliminate wave superposition generated by three hulls, minimize the wave-making resistance. Meanwhile side hulls’displacement has great influence on the ship’s frictional resistance and the wave interference among the three hulls.In this paper, ship resistance theory and calculation methods were learned, including:the empirical method, ship model experiment and numerical simulation methods, in which the application of the CFD (Computional Fluid Dynamics) numerical simulation methods in the aspect of ship viscous flow and resistance calculation was focused on. Furthermore, the viscous flow around the Wigley hull was numerical simulated based on CFD method. Then the resistance result was analysed and compared with the experiment data of the existing ship models, appropriate CFD meshing method and parameter settings of the relative calculation were obtained, providing reference for trimarans’numerical simulation calculations.Based on the research of the Taguchi orthogonal design method, parameters of the side hull such as the configuration of the side hull, displacement, transverse position, longitudinal position and other factors were optimized selected according to the parameters program. An orthogonal table contain five factors (including an error term) and 4 horizontal L16 (45) were established, to get a total of 16 groups of calculating schemes, making sure not only that the schemes were selected in science, but also the calculating time and the consumption of the resource were greatly reduced.16 sets of schemes were numerical simulated, analized and studied the influence of side hull parameters on the resistance of the trimaran, obtaining optimized parameters of the side hull based on the minimum total resistance, exploring a method to optimize trimaran’s side hull parameters.Through the study of the theory of numerical wave tank, this paper was focused on the implementation method of paddle wave-making and the related technologies of wave absorbing. The numerical simulation of 2D numerical wave tank obtained good wave-making effect. On this basis, the numerical simulation of Wigley trimaran ship’s movement in 3D regular waves verified the feasibility of the 3D numerical wave tank, laying the foundation for future research of trimaran’s movement in wave.