Research On Calculation For Ship Resistance And Optimization Of Side-hull Location Of A Trimaran

Ship speed and resistance is one of the important ship performances. As a high performance ship, campared with conventional monomers, high speed trimarans have great advantage in reducing the wave making resistance. But there are many factors affected the resistance performance of the high speed trimarans, especially the effect of the position of the side hulls. Early in the mid eighteenth century, ship model test was used to calculate the ship resistance. With the unceasing development of the computer technology and the computational mathematics, computational fluid dynamics has gradually became a powerful tool to study the ship resistance performance. In this background, computational fluid dynamics was used in this paper to study on the resistance performance of the Truss SPAR platform﹑DTMB5415 model and high speed trimarans in the calm water, and flow field was also simulated. In this paper, the specific process is as follows:First,I calculated the resistance performance of the Truss SPAR platform was towed in calm water by ship model test and numerical simulation. I analyzed the changes of pressure and velocity between the heave plates and simulated the flow at the for and aft of the Truss SPAR platform. The experiment results were close to the numerical simulation results,which showed that it was feasible to calculate the resistance of the complicated marine structures by CFD. Finally,with the method of overlapped model calculation,I analyzed the components of the resistance of the Truss SPAR platform and the results showed that the wave making resistance and viscous pressure resistance were the main parts of the resistance.Secondly, the Michell wave making resistance formula and numerical simulation were used to calculate the resistance performance of the DTMB5415 model and results of the calculation were compared with the experimental data. The results showed that the numerical simulation method gave a big advantage in calculation accuracy and the method simulated the flow field near the ship accurately.At last,I calculated the resistance performance of the high speed trimarans in eight different states and analyzed the results from the wave height distribution,the wave interference,hull pressure distribution and resistance. I found the longitudinal spacing made an apparent influence. In different longitudinal dispositions,the resistance of the high speed trimarans were different and horizontal disposition made an small effect on the resistance performance of high speed trimarans.