DEROGUE WAVES

Deterministic Forecasting of Rogue Waves in the Ocean

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 Obiettivo del progetto (Objective)

'Rogue or freak waves are short wave groups of anomalously high and steep waves (compared to ordinary sea waves) which have propensity to come seemingly out of nowhere. Such waves represent real danger even to the largest ships and offshore structures. Rogue waves cannot be prevented, but a better prediction could save lives. The present day forecasting of rogue waves is PROBABILISTIC, i.e. only the probability of freak wave occurrence in a given place and time is found as a result of wind wave modeling. The project is aimed at developing a radically new way of rogue wave forecasting – DETERMINISTIC FORECASTING. The main idea is as follows: although the sea waves are inherently random there exist situations where wave motion is constrained in a special way (e.g. wave on currents, above certain bottom topography), which decreases the number of “effective” spatial dimensions and makes deterministic forecasting possible. Such situations are characterized by particularly high risk of rogue waves. The objectives of the project are to fill the gaps in understanding of fundamental mechanisms of rogue waves and upon this basis to improve their prediction. The Fellow, one of the top scientists of his generation, is uniquely qualified to adapt the most advanced mathematical approaches developed for weakly nonlinear models to describe realistic rogue waves. The research will employ: (i) advanced analytical methods, both exact and asymptotic ones (making use of the expertise of the Host); (ii) a uniquely complete range of 2D and 3D numerical models from weakly to fully nonlinear (mostly developed by the Fellow); (iii) laboratory, in-situ and meteorological data will be used for validation of the models. The developed techniques will enable one to predict not only a high probability of a freak wave, but also WHEN, WHERE and WHAT KIND OF ROGUE WAVE to expect. This will dramatically reduce the risks involved for lives, ships, on-shore and offshore structures, and environment.'

Introduzione (Teaser)

A huge wave suddenly bearing down on a ship threatening to engulf it is the greatest nightmare for any sea captain and his crew. An EU-funded initiative investigated this potentially lethal threat.

Descrizione progetto (Article)

The 'Deterministic forecasting of rogue waves in the ocean' (DEROGUE WAVES) project developed the scientific basis for improving the forecasting of rogue waves. Rogue or freak waves comprise short groups of unusually high and steep waves, which seem to come from nowhere.

Such waves represent a significant threat to even the largest ships and offshore structures. Although they cannot be prevented, better prediction of their occurrence could save lives. At present, the only way to predict the probability of a rogue wave occurring at a given time and place is through wind wave modelling.

Sea waves are inherently random, but situations exist where wave motion may be constrained in a particular way. These include in the presence of currents or above certain types of seafloor, which reduce spatial dimensions and make deterministic forecasting possible. Such situations are typified by a particularly high risk of rogue waves.

The project provided a more complete picture of the mechanisms behind rogue waves, thereby improving the basis for their prediction. This was achieved through the application of advanced mathematical techniques and the use of 2D and 3D numerical models.

Models were validated using laboratory measurements and in situ and meteorological data to provide a better understanding of the properties and dynamics of extreme short wave groups. This enabled short-term deterministic rogue wave forecasting to be established. An important feature of rogue waves was found to be that they frequently comprise a high crest followed by a deep trough.

DEROGUE WAVES also proved the existence of very steep structurally stable solitary wave groups over deep water and identified their key parameters. In addition, the project explained the evolution of individual rogue waves as well as intermittent rogue wave events, which last for a significantly longer time.

A theory for waves trapped in fast currents was further developed. Computer simulations were also conducted to confirm the existence of the effect of trapped waves over deep water, causing rogue waves to occur.

The project's success will enable scientists to accurately predict not only the probability of a freak wave, but also when, where and what type of rogue wave to expect. This information will help to dramatically reduce the risk to sea farers' lives, ships, and onshore and offshore structures.