Saturday , December 5 2020

The continuing mystery of the towering bad waves of the sea

3 PM. On the first day of the new year in 1995, the operation was stopped on the deck of the Norwegian Draupner oil platform, which was isolated in the middle of the intense North Sea. The wind was too strong, and the waves were blown down. It was not safe to be outside anymore.

But one wave has deviated from the other. We measured a height of 84 feet, about 2.5 times the height of the pole, and named it "Draupner wave". Luckily, the monstrous expansion did not reach the deck of the platform.

The Draupner wave is the first scientific evidence of a rare bad or odd wave that appears suddenly and is at least twice as much as the surrounding waves. This momentous phenomenon is thought to be the possible culprit for sinking the ship in the undersea yet.

There is still uncertainty as to how bad waves form, but the engineering scientist team has successfully simulated how monster waves suddenly float out of the ocean. The researchers recreated a small version of the Draupner wave in the simulation pool Journal of Fluid Dynamics.

"There is a bit of heated debate about the physical mechanism of how these things form," said Mark McAllister, co-author of the study, a mechanical engineer at Oxford University. "We showed the conditions to support such wavelengths."

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"data-credit-provider =" User-defined type "data-caption =" Left: Simulated wave. Right: Hokusai's "Great Wave" (early 1830s). "title =" Left: Simulation wave. Right: Hokusai's "Great Wave" (early 1830s). "src =" jpg? signature = ZImDdwMoTv353wVRYmyhkDLH9_g = & source = https% 3A% 2F% "alt =" Left: Simulated wave. Right: Hokusai's "Great Wave" (early 1830s) "data-fragment =" m! 2917 "data-image =" -a39b-4dc9867ed5c5.jpg% 252Foriginal.jpg? signature = GA_DKfPGMATb0plF5fh_9byu3y4 = & source = https% 3A% 2F% "data-micro =" 1 "/>

Left: simulated wave. Right: Hokusai's "Great Wave" (early 1830s).

Image: University of Oxford / The University of Edinburgh

A series of waves in an 82-foot diameter test tank at The University of Edinburgh, designed to create real ocean conditions, proved that odd waves form when a series of waves cross each other at a large angle (about 120 degrees).

Günter Steinmeyer, a physicist at the Max Born Institute in Germany, said Günter Steinmeyer, a physicist at the Nonlinear Optical and Single Pulse Spectroscopy Laboratory, who studied steep waves, is an important part of the puzzle.

Twenty years after the still famous Draupner incident, we still do not know about this little wave.

"About 20 years later we firmly believe they exist, but there are many explanations," said Steinmeyer, who had no role in the study. "They are very rare."

"If you ask three scientists in the field, you'll probably hear four stories, and all the other explanations are completely wrong," he added.

To create the Draupner, engineers spent about two days sending waves to each other at various angles until they found the right combination. The wave appeared as a "great wave of Kanagawa" from the early 1830s, a famous woodcut by Hokusai painters.

"The similarity with Hokusai's Great Wave was purely coincidental," said Samuel Draycott, an engineer and research co-author at the University of Edinburgh.

"Only a few months later, I read the theory that the great waves of Hokusai can actually describe so-called fake waves," Draycott added.

A spokesman for Draycott said the monster waves were reported near the coastal waters and the coast. So when you understand the point at which a malignant wave can occur, sailors or people working at sea can know when conditions are ripe for the villain, like two storms approaching from various angles.

Simulated Draupner wave about 1 meter high.

Simulated Draupner wave about 1 meter high.

Image: University of Oxford / University of Edinburgh

"There is a theory that says random," McAllister said. "Others say that if there are certain conditions, the waves will grow taller."

Although Steinmeyer says, some fake waves still have a lot of opportunities.

The weather must be right (possibly a storm). The waves from the other direction must collide with the correct time and at the right angle, as you did next to the Draupner platform.

"It's a statistically very small number," Steinmeyer said. However, he reported that for decades some of the ship captains in the sea had discovered a huge Draufuner wave.

The Draupner wave in 1995 at least gave the workers frustrated by storms in the northern waters, but they were not injured.

"Fortunately, the platform did not hit the deck because the platform was high enough," it could have been very catastrophic if it were lower. "

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