International Journal of Ocean and Coastal Engineering

In the recent years, various geo-synthetic components find an extensive application in civil and coastal engineering practice. Commonly, geo-synthetics have a wide application for secondary or tertiary purposes, such as filtration, separation, barrier, reinforcement, whereas, they can be potentially exploited for various other applications in the coastal engineering practice. A sustainable seawall cross-section comprising different geo-synthetic products was proposed to be erected along the Pallana Beach ($19^{\circ }17^{\prime }55.19^{\prime \prime }$ N and $76^{\circ }23^{\prime }18.55^{\prime \prime }$ E), located in Alleppey district of Kerala along the south-west Indian coastline. Since the subsoil at the location is poorly graded, it was decided to replace the conventional materials like rock boulders and concrete armour units with geo-synthetic products. A comprehensive physical model study was conducted to assess the hydrodynamic performance (i.e. reflection, run-up, and pressure distribution) of the geo-synthetic seawall cross-section for a wide range of random wave characteristics and two water depth conditions. The relative overtopping rates for the seawall at varying water levels are computed conservatively from the guidelines prescribed by the EurOtop Manual and XGB Overtopping model.

In the 1990s, oceanographers realized that the freak waves posed realistic threats to offshore and marine engineering. Since then, tremendous efforts from both academia and industry have been made to reveal the physics of freak waves as well as their effects on structures. Despite the need for a uniform and robust definition and the ongoing discussion of the dominant mechanism, significant advances have been achieved in understanding freak waves in various aspects. As an emerging explanation of freak wave formation, the nonequilibrium dynamics has received much attention, as it provides insights into nonlinear focusing under complex changing environmental conditions. The new techniques for the generation or reproduction of freak waves are of higher efficiency and accuracy in terms of enhancing maximum wave height and controlling the focusing position and time. Besides, sidestepping the complex physical mechanisms, the machine learning, as a data-driven technique, provides an alternative approach for the investigation of freak waves. Tracking these new developments is the target of this review paper, the limitation of the current works and future perspectives are also discussed.