Multi-objective hydrodynamic optimization for ONR tumblehome ship

A numerical multi-objective optimization procedure is proposed here to describe the development and application of a practical hydrodynamic optimization tool, OPTShip-SJTU([14,15]). Three components including hull form modification module, hydrodynamic performance evaluation module and optimization module consist of this tool. In this paper, the free-form deformation (FFD) method are utilized as parametric hull surface modification techniques to generate a series of realistic hull forms subjected to some design constraints during the optimization process. In performance evaluation module, Neumann-Michell (NM) theory is employed here to predict the wave-making drag at low computational cost. Additionally, Kriging models are established based on OLHS samples as surrogates for optimization process, and a multi-objective genetic algorithm named NSGA-II has been employed to provide pareto-optimal front. ONR Tumblehome model 5613 is taken as preliminary design, and the two objective functions have been chosen as the wave resistance at two speeds (Fr = 0.2, 0.3), Eventually, the pareto optimal set which provides over 4000 optimal hull forms is obtained by using NSGA-II algorithm, and three of them are chosen for further analysis. The numerical optimization results are analyzed, and the availability of the OPTShip-SITU is confirmed by this application.