Tertiary wave interactions effects upon large floating structures

Tertiary wave run-up on floating bodies is considered here. Linear potential flow theory is adopted and third-order effects are taken into account through non-linear interactions between incident and diffracted-radiated wave fields, resulting in wave number change of each component due to the interaction with the others. The numerical procedure consists of updating both fields by means of iterations, yielding a steady-state solution in frequency domain. In the present paper, Molin et al. (2005) parabolic model is implemented in a general 3D-BEM seakeeping code, allowing for the assessment of third-order interaction on practical units of general shapes. In addition, the same approach is extended to irregular waves. Results of the presented numerical model are compared to experimental data with both regular and irregular waves. The obtained results show an excellent agreement with model tests, and provide better estimation of wave elevation compared to linear analysis. Thus, bringing this theory into an industrial practice can play a key role in the selection of critical wave conditions leading to green water events. Extensive investigations on the sensitivity to computational parameters (such as domain size, discretization, etc.) are also presented.