Scientists from the USA, Ireland and France were able to explain the nature of the so-called anomalous waves, which are single giant waves that suddenly appear on the surface of the deep ocean. The ships that have fallen under their "mighty hand" usually have no chance of salvation.
Mysterious and deadly killer waves rise more than 25 m. They are dangerous not only in size, but also because of their unpredictability - their appearance cannot be predicted. Such waves can overtake sailors at the most unexpected moment and disappear without a trace in just 20 seconds.
Until now, scientists have failed to understand the nature of their occurrence. Professor Francesco Fidel and his colleagues have opened the veil of secrecy. Thanks to ten years of observations of the attacks of anomalous waves on the North Sea platforms, the team concluded that they had a single mechanism of behavior. Scientists see the reason for the formation of such waves in the resonance effect - situations when not very large groups of waves move towards each other at a special angle at certain intervals and, during a collision, generate a three-dimensional structure, which is characterized by a sharp convex crest and a gently sloping base. Then all the energy of the colliding waves sets the direction of movement of the rogue wave. Due to the general nonlinearity of the ocean and the broken symmetry of the structure of anomalous waves, they acquire an additional 15-20% of the height and are further enhanced by the resonance effect.
The model developed by scientists is based on a directional wave spectrum that analyzes the energy of the flows. The finished model made it possible to see the principles of the formation of anomalous waves by different combinations of wave groups. The theoretical predictions made using this model coincided with real events on oil platforms that occurred in 1995, 2007 and 2015.
Thus, according to Professor Fidel, the nature of rogue waves lies in a rare combination of wave groups colliding with each other.
The specialists intend to continue studying the nonlinear resonant source of anomalous waves in the hope of finding a way to predict their occurrence in order to timely warn ships of an impending threat.
The research is published in Scientific Reports.