To meet the requirements for green ships in the IMO ship Energy Efficiency Design Index, based on the self-developed ship form optimization platform (SHIPMDO-WUT), the KCS ship is regarded as the initial hull to reduce its wave-making resistance at a certain speed. The hull form modification is then implemented by the radial basis function (RBF) interpolation technology and the resistance evaluation is carried out by the NM (Neumann-Michell) potential flow theory solver to minimize the wave-making resistance combining with the NSGA-II algorithm. Finally, after completing the optimization of ship resistance performance at the speed of Fr=0.3, the optimized ship is selected for analysis, and the resistance reduction effect of the optimized ship is analyzed through STARCCM+ software.
The research results show that: (1) The hull form modification module based on radial basis interpolation technology can produce a smooth hull profile; (2) For the KCS ship, under the premise of meeting the engineering constraints, the automatic optimization method of the hull surface based on numerical simulation can obtain a new ship form with better performance of resistance.
Ship hull form optimization is one of the effective methods to achieve energy saving and emission reduction. With the development of computer technology and Computational Fluid Dynamics (CFD), its evaluation capability has been enhanced, simulation-based design (SBD) has been listed as a hot issue in the research of numerical simulation technology by the International Tugboat Conference (ITTC), and many scholars at home and abroad have conducted extensive research on ship hull form optimization.
Kim (2009) modified Wigley hull profile based on parametric hull representations and NURBS surfaces and Peri et al. (2001) utilized Bé zier Patch to complete the modification of hull geometry. Based on the Rankine source method, Zhang and Percival et al. (2012) obtained an optimized ship hull form with minimum wave-making resistance. Wan Decheng et al. (2020) carried out local deformation of bow, waterline and aft of luxury cruise ship by the FFD (Free-Form Deformation) method, combining with the Neumann-Michell (NM) potential-flow-based solver NMShip-SJTU to complete the optimization of wave-making resistance at the two specified speeds. Shen Tong et al. (2013; 2015) used the radial basis function interpolation method and combined with the hydrodynamic solver Shipflow to optimize the wave-making resistance of KCS and S60 ships, and obtained the ship type with better resistance performance, but the displacement of the optimized ships was reduced, which reduced the ship operation economy to some extent. Hu Chunping et al. (2012) completed the full parametric modeling of KCS by using parametric modeling software CAESES, and combined with hydrodynamic calculation software to complete the study of automatic optimization of KCS profile. Zhan et al. (2012) used a fusion deformation method to generate a series of bulbous bows, realized the automatic optimization of the bulbous bow profile, and got the ship type with less wave-making resistance.
