Numerical study of wave forces on truncated cylinder arrays generated by focused waves

Vertical cylinders are commonly used as foundation supports in offshore engineering. Wave forces on a single cylinder have been widely studied and developed into methods for calculating wave loads. However, wave forces on truncated cylinder arrays, representing floating foundations, have been rarely investigated. In this study, the wave forces on truncated cylinder arrays in 2 × 2 and 4 × 4 configurations generated by focused waves were numerically studied. The numerical model was established with the volume of fluid (VOF) method and the k-ω SST turbulence model based on OpenFOAM. The model accuracy was validated against experimental data from literature. The array effect was discussed by comparing the characteristics of wave forces on truncated cylinders at different positions. It was found that there is a nonlinear relationship between wave forces on cylinder arrays and wave amplitude. The wave force distributions of cylinder arrays show strong symmetry relative to wave incidence, with minimal amplitude variations across columns, while enlarged arrays amplify phase modulation. Surrounding cylinders provide significant sheltering effects to inner cylinders. Besides, the spectra of wave force on truncated cylinders were modulated by the spectral characteristics of incident focused waves. An empirical prediction method based on peak wave frequency was proposed to estimate dimensionless wave forces and their spatial distribution within cylinder arrays. This study enhances the understanding of wave force distributions on cylinder arrays under extreme wave and provides valuable insights into structural design of offshore structures.