An efficient focusing model of freak wave generation considering wave reflection effects

• An efficient focusing model for freak wave generation has been developed.
• The developed model exhibits good performance in generating extremely high waves.
• Wave reflection is proven to be a possible factor of freak wave formation.

This study investigates the generation of freak waves using a new focusing model that considers the effects of wave reflection. In the developed model, wave spectrum energy is divided into three parts: one for random waves, one for forward transient waves, and one for backward reflected waves. In order to test this model, a numerical wave tank (NWT) is set up and validated through comparison with published experimental results. Numerical simulations are conducted and the simulation results are compared with those of simulations based on Kriebel’s focusing model. The comparisons show that the developed model is capable of generating extremely high waves in an accurate and repeatable manner. The primary advantage of the developed model is that both the forward transient waves and the backward reflected waves contain only half the energy of the transient waves in Kriebel’s focusing model, making it much better at easing wave breaking. In addition, the numerical simulations indicate that wave reflection could be a possible factor that contributes to the formation of freak waves.