ABSTRACT
Numerous attempts have also been made to explore the possibility of using deterministic nonlinear wave theories to predict the evolution of a random wave field. Rapid advancements in both theoretical and experimental studies have taken place since the sideband instability of weakly nonlinear Stokes waves was discovered by Benjamin & Feir (1967). One of the important theoretical models for studying the instability and the long-time behaviour of nonlinear water waves was developed by Zakharov (1968), who deduced an integral equation for infinitely deep water to describe the near-resonant interactions between waves at the lowest possible order, from which the Nonlinear
1 INTRODUCTION
In the past decades, waves of anomalously large size, called abnormal, freak or rogue waves have been observed in the ocean and reported to cause severe damage to offshore structures and ships. Due to their strong nonlinearity and rare possibility in reality, the research on their physical mechanism and wave-induced structural loads as well as responses is still very limited.
