Multi-objective optimization of trimaran sidehull arrangement via surrogate-based approach for reducing resistance and improving the seakeeping performance

Trimaran hull forms have been very attractive in the past decade. Hydrodynamic performance of trimaran ships is influenced by sidehull arrangement. The present study was intended to construct a surrogate model for better understanding of the hydrodynamic performance of a trimaran ship. Accordingly, seakeeping and resistance of an inverted-bow trimaran were considered as objectives of a simulation-based design (SBD) optimization framework. Different longitudinal, transversal, and vertical position of trimaran’s sidehull were investigated based on an advanced free-surface steady Reynolds-averaged Navier–Stokes (URANS) solver within StarCCM+ for resistance calculation and 3D panel method in Ansys-AQWA for seakeeping analyses. Quality and applicability of metamodeling optimization and its computational time were examined for future trimaran hull design projects. Total resistance for drag reduction, pitch and heave motion, and vertical acceleration at fore perpendicular for seakeeping performance were objectives of the study. The optimization results indicated a 6.9% drag reduction and 4.7% improvement in seakeeping performance, which yield lower longitudinal and large transversal distances of the sidehull. Furthermore, the conducted investigations demonstrated the effectiveness and capability of the proposed optimization platform for other marine industrial projects.