Numerical study of the interaction between peregrine breather based freak waves and twin-plate breakwater

Abstract

Freak wave is a kind of extreme and unexpected surface wave with great wave height and energy, which might happen in different ocean areas such as the deep-sea zone and offshore zone. Coastal, offshore and marine structures such as harbors, ships, platforms and very large floating structures built in various ocean areas might be prone to be threatened by ocean waves, especially by extreme waves like freak waves. However, although researchers have already proposed and studied many types of breakwaters to protect structures from damage by ocean waves, few research has been done on the interaction between freak waves and breakwaters. This paper aims to study the interaction between freak waves based on Peregrine breather solution and twin-plate breakwaters, including the characteristics of interaction phenomena, transmitted wave surface, wave loads and structural responses. Firstly, a 2-D numerical wave tank is built in which the simulations are conducted using computational fluid dynamics (CFD) approach, while a strong-coupled fluid–structure interaction (FSI) algorithm is applied to consider the hydroelastic effects. Secondly, validations of the interaction between regular waves and single/twin-plate breakwaters are performed to show the effectiveness of the numerical method. Eventually, simulations of the interaction between freak waves and twin-plate breakwaters are carried out, in which the phenomena are shown and results are analyzed. Effects of carrier wave height and carrier wave length of freak waves are further considered respectively. Hydroelasticity excitation caused by severe slamming is observed and analyzed during the FSI process.