Comparative study on analysis methods for added resistance of four ships in head and oblique waves

This paper presents a comparative study of wave-induced motion responses and the added resistance of a ship. Four representative types of ships are adopted as test models: LNG carrier, tanker, containership, and bulk carrier. Two experimental techniques-captive and free-running model tests-are conducted under regular head and oblique wave conditions to create benchmark data. Several numerical computation methods (asymptotic formula, 2D strip theory, 3D panel method, and CFD) are applied to perform the seakeeping analysis. The comparison results indicate that the accuracy and reliability of each analysis technique are validated, and its characteristics and limitations are investigated with respect to the physical aspects of the added resistance caused by a wave. The analysis results are compared based on how steady flow-induced coupling effects are considered. Further, the sensitivities of seakeeping quantities with respect to wave steepness were examined based on the results of linear and fully nonlinear computations. The overall tendency of the added resistance in accordance with the incident direction of a wave is discussed.