Freak ocean wave recreated in testing facility
Researchers have recreated the famous Draupner freak ocean wave, which occurred in the North Sea in 1995.
A scaled-down version of the wave, which was among the first to be observed in the ocean, was produced using the University’s testing tank, FloWave.
Their study sheds light on the maritime conditions that lead to freak waves.
These are believed to cause catastrophes such as the sinking of large ships, but are not well understood.
Researchers hope that their study will lay the groundwork for predicting these potentially catastrophic waves.
The Draupner wave, observed on 1 January 1995, was about 25 metres high. Its measurements were made from the Draupner North Sea platform.
Freak waves are unexpectedly large in comparison to surrounding waves. They are difficult to predict, often appearing without warning.
The team of researchers at the Universities of Oxford and Edinburgh set out to reproduce the Draupner wave under laboratory conditions.
They recreated it using two smaller wave groups, by varying the angle at which the two groups collide.
It was possible to reproduce the freak wave only when the two groups of waves crossed at approximately 120 degrees.
The observation not only aids understanding of how the famous Draupner wave may have occurred, but also highlights the nature and significance of wave breaking in crossing sea conditions for the first time.
The recreated wave bore a resemblance to a famous depiction of a wave in art - the Japanese artist Katsushika Hokusai’s early 1800s woodblock print ‘The Great Wave off Kanagawa’, also known as ‘The Great Wave’.
Hokusai’s wave, which threatens three fishing boats in the shadow of Mount Fuji, is believed to depict a freak wave.
The laboratory-created wave also bears strong resemblances to photographs of real ocean freak waves.
Experiments were carried out in the FloWave Ocean Energy Research facility at Edinburgh, a circular combined wave-current tank with wavemakers around its circumference. The findings were published in the Journal of Fluid Mechanics.
Not only does this laboratory observation shed light on how the famous Draupner wave may have occurred, it also highlights the nature and significance of wave breaking in crossing sea conditions. The latter of these two findings has broad implications, illustrating previously unobserved wave breaking behaviour, which differs significantly from current state-of-the-art understanding of ocean wave breaking.
This unique capability enables waves to be generated from any direction, which has allowed us to experimentally recreate the complex directional wave conditions we believe to be associated with the Draupner wave event.
The measurement of the Draupner wave in 1995 was a seminal observation initiating many years of research into the physics of freak waves and shifting their standing from mere folklore to a credible real-world phenomenon. By recreating the Draupner wave in the lab we have moved one step closer to understanding the potential mechanisms of this phenomenon.