CFD-based multi-objective optimization of a waterjet-propelled trimaran

Abstract

In the present paper, the multi-objective optimization of a waterjet-propelled trimaran was carried out based on computational fluid dynamics (CFD) considering the interactions between the waterjet and the hull. Numerical results were validated with experimental data for one waterjet propulsor and the original hull. The simulation-based design (SBD) optimization was performed for the waterjet and the hull. Furthermore, the parametric reconstruction of the duct was executed based on its shape characteristics. The Lackenby method and the free-form deformation method were applied to transform the hull shape. The optimal Latin hypercube design (Opt LHD) method was used to generate samples, and the surrogate model was developed based on the support vector regression (SVR) method. The non-dominated sorting genetic algorithm II (NSGA-II) was employed to optimize design objectives at the design speed of Fr = 0.628. In comparison to the original shape, the total resistance, the thrust, the torque, and the power consumption of the optimized trimaran at self-propulsion, respectively, decreased by 3.85%, increased by 6.38%, increased by 1.73%, and decreased by 10.39%. Therefore, it can be inferred that the SBD technique is effective to solve multi-objective optimization problems of ship hydrodynamics.