Research on Design Optimization of High-Speed Ship Bulbous Bow Based on Nelder-Mead Algorithm

Abstract

In order to reduce the wave-making resistance of ships, this paper proposes an optimization design method for bulbous bow form based on potential flow theory. In this paper, we restrict our interest to parametric deformation of the bow, at the same time constrain the displacement and the length of the ship. Based on Rankine source method, the wave-making resistances of DTMB5512 and ITTC Ship A-2 are calculated. For optimization, Sobol algorithm is selected to create sample space; based on it, we use Nelder–Mead algorithm to obtain the optimal hull form in the space. Additionally, we compare and analyze the hydrodynamic performance of the ship. The results show that the optimization design method reduces the wave-making resistance of DTMB5512 and ITTC Ship A-2, which verifies the feasibility of the method. Energy Efficiency Design Index (EEDI) guides the future development of the shipbuilding industry toward green ships and accelerates the pace of energy conservation and emission reduction. EEDI is closely related to hull form; therefore, the design optimization of ship hull focus on reducing EEDI becomes the central issue of the current research (Hou et al. 2018).