Hull form optimization of trimaran using self-blending method

A ship hull modification method called self-blending, combined with CFD (Computational fluid dynamics) and MIGA (Multi-island genetic algorithm), has been developed and applied to the optimization of a trimaran. The modification of ship hull has been carried out through merging the given cross sections picked from the original ship hull. Six parameters are used to perform the hull form modification, three of which are self-blending parameters of the main hull. For the other three, two being the parameters of controlling the relative location of side hull, the rest one being length ratio of new side hull to original side hull. Verified CFD method is used to evaluate the objective function (CT, coefficient of total resistance of the vessel). A RS (response surface) has been built to reduce the computation expense of optimization. The coefficient of total resistance of the optimized vessel decreases about 21.34% in comparison with the original hull which proves that the methods are valid for optimization of the trimaran.