Extreme waves in deep waters, characterized by abnormally high crest elevations, steep wave fronts and breaking wave crests, have been reported occasionally over the past decades, if not longer. Although the physics of the interactions between such waves and marine structures are still not well understood, it is generally accepted that the loadings associated with such waves, especially if there is a wave impact, are among the highest and most damaging. The occurrences of such extremity are rare and highly localized in both space and time. However, as captured in the now well-known North Sea event at the Draupner E Platform in 1995, such extreme waves can “hit” a structure.

Over the past 30 years, quite a number of studies have been conducted to better understand the physics of extreme wave loading. These include both highly controlled experiments in wave flumes/basins, and numerical modeling using high performance computing capabilities. Through advanced flow visualization techniques, high speed photography and carefully designed pressure-sensing systems, experimental studies have helped to elucidate the kinematics and dynamics of extreme wave loading. However, experimental studies could only provide discrete descriptions of the impact process, including snapshots of the wave front during impact and the impact pressure time histories at discrete locations. With entrained air bubbles and turbulent mixing in the impact process, much of the details in the vicinity of the local impact zone are typically not well captured.

With the advancement in computational technologies, several numerical methodologies are now able to model the evolution of the incident wave front prior to impact. The modeling of the highly nonlinear physics in the near-field of the impact zone, however, remains a challenge. Very few numerical methodologies, if any, is able model the “flip-through” during impact and the associated impulsive pressures adequately.

This lecture presents what we now know about extreme waves and their forces on marine structures, derived mainly from controlled experimental studies and numerical models that are adequately designed to capture the physics. The lecture will also discuss the uncertainties involved and how these may be addressed in the design of marine structures in deep water harsh environments.

For online registration, click HERE.