A Review on Directional Focusing Waves: Generation Methods Toward 3D Idealization of Rogue or Extreme Waves in Laboratory

In the field of ocean engineering, rogue waves have been a critical phenomenon demanding attention over the past few decades, with their visible occurrence and their influence on the marine structure being repeated. The random isolated extreme events have posed a challenge in our ability to develop a well-defined description of such waves. There have been several studies in the past on the simulation of these events in 2D using experimental facilities and numerical tools with different theoretical approaches. However, completeness in the description of the extreme events is questionable owing to the non-consideration of their directionality. The three-dimensional studies are predominantly numerical in the literature, and 3D laboratory studies are scanty due to the challenges involved and thus, leading to an incomplete description of the rogue waves and their characteristics. A comprehensive theory should represent a physical representation of the scenario and simulate these events in numerical or experimental work. Based on this background, one could provide a wave field statistical distribution. However, we are yet to reach and gain an insight into the phenomenon. Nevertheless, it is imperative to understand where we are and the central questions to achieve the target. This paper is intended to give a comprehensive review of literature narrowing down to simulation challenges and the generation of these three-dimensional waves in laboratories. Furthermore, a simplified method used to generate the focused directional wave in deep water is briefly discussed. Also, the paper reports the preliminary results of the 3D directional focusing waves with different breaking scenarios for deep water conditions in the wave basin facility at the Department of Ocean Engineering, IIT Madras.