With the continuous development of the shipbuilding industry and shipping business, hydrodynamic optimization of hull forms has drawn the attention of both academia and industry. This paper reports the details of an efficient, numerical, design optimization tool for hull form for container ships. This tool is composed of three functional modules: hull form deformation, hydrodynamic performance prediction, and optimization. The free-form deformation (FFD) and radial basis function (RBF) methods are employed to modify the ship hull globally and locally, respectively. To reduce the cost of the numerical optimization, which is always a challenging problem, a new potential theory, the Neumann-Michell (NM) theory, and the approximation model are adopted. In addition, the analysis of variance (ANOVA) method is used to represent the influence of each design variable on the objective functions. The high efficiency is illustrated by the optimization for a container ship. Wave resistance coefficients at three design speeds are minimized, and a Pareto front of solutions is obtained. The optimal hulls are verified and analyzed by the NM theory and a Reynolds-averaged Navier-Stokes (RANS)-based computational fluid dynamics (CFD) solver. Numerical results confirm the availability and reliability of the optimization tool described.

Introduction

In recent decades, with the continuous development of the shipbuilding industry and various shipping businesses, hydrodynamic optimization of hull forms has drawn the attention of both academia and industry. The economic efficiency of container ships, in particular, depends mainly on hydrodynamic performance. To obtain a hull form with the best hydrodynamic performance, design engineers have devised some approaches with different hydrodynamic analysis methods, geometrical modification techniques, and optimization algorithms. However, because of the complexity of ship hydrodynamics and the great number of evaluations of objective functions in optimization, ship hull optimization is quite time consuming. To solve this problem, a combination of a new, efficient hydrodynamic analysis method and an approximation model is adopted as a feasible scheme for ship hull optimization.

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