A numerical study on the nonlinear effects in focused wave modelling and forces on a semi-submerged horizontal cylinder

This paper concerns on the propagation of transient wave groups, focusing at one point in time and space to generate large waves. A numerical wave tank is developed based on the commercial software package FLUENT. Velocity inlet method is applied to reproduce the focused waves in this model, and the results are compared with linear and second-order theoretical results. The continuous wavelet transform is employed to analyse the time–frequency characteristics of the focused waves. Forces due to focused waves acting on a semi-submerged horizontal cylinder is investigated and compared with the regular wave sharing with identical wave crest height and trough-to-trough period. Secondary load cycle is observed which may cause “ringing”. This developed model is expected to serve as a basis for strongly nonlinear waves, such as freak waves.