Modeling wave and spectral characteristics of moored ship motion in Pohang New Harbor under the resonance conditions

Abstract

An integrated mathematical model is demonstrated to investigate the wave and spectral characteristics of the moored ship motion in an irregular geometrical domain due to diffraction, refraction, and partial reflection induced by incident ocean waves. The incidence angle of partial reflection boundary is assumed as zero. Fluid domain is divided into three regions entitled as bounded region (harbor), unbounded region (open sea), and ship region. A combined numerical approach including 3-D Boundary Element Method (BEM) in the ship region and a 2-D BEM in bounded region is performed to analyze the moored ship motion under the resonance conditions. Our proposed model is validated with existing well-known models, such as Sawaragi et al. (1989) and Takagi et al. (1993), revealing that it could efficiently capture the spectrum of waves. Then, the proposed numerical scheme is implemented in realistic Pohang New Harbor, which is situated in the southeast part of South Korea. The spectral characteristics of a moored ship motion are obtained under different directional incident waves with resonant frequencies. The reliable calculation results suggest that this method can be utilized for the safety and hazard mitigation of the moored ship in realistic harbor with complex geometry including sharp corners.