Numerical study for slamming loads on the bow of a ship-type FPSO model under breaking waves

Numerical analyses were performed to investigate the characteristics of the slamming impact loads on the bow-flare of a ship-type floating production storage and offloading (FPSO) model under breaking waves. To estimate the slamming impact load, a series of breaking wave simulations was performed. From 2D wave flume tests, the grid aspect ratio, convection scheme, turbulence model, effect of surface tension, and grid dependencies were investigated. Through a series of numerical simulations, the grid system and numerical schemes were determined, and the slamming impact load simulations were conducted. It could be observed that the slamming impact loads and motions of the FPSO model in the numerical simulations were in good agreement with the experimental results. In order to investigate the relation between the slamming impact load and free motion of the FPSO model, the breaking impact simulations were performed under fixed positions and the free motion of the FPSO model. From the results, the relation between the relative angle and slamming impact load, as well as the relation between the position of the FPSO model and impulse response, are discussed. •For the purpose of generating high-intensity breaking waves in Computational Fluid Dynamics (CFD), various case studies were conducted, including turbulent models, the effect of surface tension, grid aspect ratios, mesh resolutions and discretization techniques for convection terms.•To accurately simulate breaking waves, a grid system with an aspect ratio of approximately 2 is necessary, along with a second-order convection scheme. Turbulence models and surface tension effects are found to be insignificant in breaking wave simulations. However, in deep-water conditions, additional meshes under the free surface are crucial to capture the distribution of wave velocity to greater depths.•In analyzing slamming impact loads under breaking wave conditions, the highest impact loads shifted in location based on changes in wave headings, influenced by relative angles between the wave and the FPSO model's bow. Trends in numerical simulations closely mirrored experimental observations.•This study identified the relative angle between the breaking wave and the FPSO model's bow as the primary factor influencing breaking impact loads. Accurate prediction of wave characteristics and relative angle enables the estimation of slamming impact load magnitude. Additionally, under fixed FPSO model conditions, impulse responses ar