"Optical rogue waves reveal insight into real ones"
Posted on 12/04/2022 6:57:06 AM PST by Twotone
One passenger was killed and four more injured after a "rogue wave" hit a cruise ship bound for Antarctica, travel company Viking has said. The Norwegian-flagged Viking Polaris was caught in a storm as it sailed towards Ushuaia, Argentina on Tuesday. The victim was a US woman who died after being struck by shattered glass, Argentinian media report.
(Excerpt) Read more at bbc.com ...
Sea captains have been reporting these rougue waves for hundreds years and were always dismissed until fairly recently.
Climate change?
Rogue wave? WTH is a rogue wave?
Large wave...
Very large wave...
But...rogue? What? It’s wandering around the ocean looking for a hapless cruise ship to attack?
Sheesh!
“Climate change?”
Isn’t everything? 😏
Despite the popularity and charm of cruise ships, they are still more dangerous than staying on land. Things can go wrong, and when they do, the ship is far from land and hospitals.
Visiting Antarctica is on my bucket list.Years ago I was planning to go on one of those Air New Zealand flights that flew over the continent...but after one of them crashed they stopped them.
From Wiki:
“Rogue waves are unusually large, unpredictable, and suddenly appearing surface waves that can be extremely dangerous to ships, even to large ones.”
In Daytona one time for a nascar race, on the way to the track we kept seeing tow trucks carrying cars that were covered in sand. A LOT of ‘em.
Later that evening the local news reported a 14 foot rogue wave hit Daytona Beach.
They just come out of nowhere.
rogue
1. An unprincipled, deceitful, and unreliable person; a scoundrel or rascal.
2. One who is playfully mischievous; a scamp.
3. A wandering beggar; a vagrant.
4. A vicious and solitary animal, especially an elephant that has separated itself from its herd.
5. An organism that shows an undesirable variation from a standard.
well with a bow shaped like that, i’m surprised all the front windows werent smashed out as well... that ship cannot take on anything bigger than 20ft seas i would guesstimate...
As fronts move past an area on the sea, the direction of the strong wind fields also change.
This means you can have day-old waves from one direction, and a complete arc of wave directions to include the newer waves built by the newer wind direction.
When you have big wave trains from several directions, you can get “nodes and anti-nodes.”
Let’s say you have some (not all) 30’ waves from the west, 25’ waves from the NW, and 20’ waves from the N.
If you are in just the right place at just the right time, those waves can combine to make a short-lived “super-node” more than 50’ high.
“According to the National Oceanic and Atmospheric Administration, rogue waves can be double the size of surrounding waves. They often come unexpectedly from directions other than that of the prevailing wind.”
“In oceanography, rogue waves are more precisely defined as waves whose height is more than twice the significant wave height (Hs or SWH), which is itself defined as the mean of the largest third of waves in a wave record. Therefore, rogue waves are not necessarily the biggest waves found on the water; they are, rather, unusually large waves for a given sea state. Rogue waves seem not to have a single distinct cause, but occur where physical factors such as high winds and strong currents cause waves to merge to create a single exceptionally large wave.”
But are they sure it was not a “vast right wing” “rogue wave”?
"Optical rogue waves reveal insight into real ones"
[Text goes with optical comparison image above.]
https://phys.org/news/2016-02-optical-rogue-reveal-insight-real.html
Rogue waves in the middle of the ocean often appear out of nowhere and vanish just as quickly. But in their short lifetimes, they can generate walls of water 15 to 30 meters (50 to 100 feet) high, crashing down with enough force to sink even the largest ships. Although rare, when rogue waves do occur they often take ships by surprise because their formation is not well-understood, and so they are difficult to detect in advance.
Since tracking down a rogue wave in order to study it would be difficult and dangerous, researchers have come up with another way to study these waves: creating a small-scale optical version in the lab that forms by similar underlying mechanisms, except in light instead of water. In the past few years, scientists have realized optical rogue waves in optical fibers, photonic crystals, and other optical systems.
Now a team of researchers, Christopher J. Gibson, Alison M. Yao, and Gian-Luca Oppo at the University of Strathclyde in Glasgow, Scotland, has proposed a new way to produce optical rogue waves in a two-dimensional space. Their work is published in a recent issue of Physical Review Letters.
“By understanding the mechanism for generating rogue waves, we can devise methods to detect their precursors—in our case, multi-vortex collisions,” Oppo told Phys.org. “By knowing where there is a high probability of rogue waves occurring, ships can change course to avoid catastrophic events.”
In the new proposed mechanism, optical rogue waves could form by a sequence of events that starts with a small instability in the regular wave pattern. This pattern instability first leads to a phase instability (the waves’ shapes begin to change), which then leads to an amplitude instability (the waves’ heights begin to change), which eventually creates swirling vortices. If there are enough vortices, then multi-vortex collisions can occur and produce a large, short-lived spike—the optical equivalent of a rogue wave.
“We can realize vortex-mediated turbulence to channel large powers into a single, huge, narrow peak of light,” Gibson said.
As the researchers demonstrated, these peaks of light can be up to 27 times higher than the average fluctuation. In oceanography, waves with peaks 8 times larger than the average wave are already considered very dangerous.
“Experience the wonders of sea travel and visit exotic ports of call!”
- brochure for cruise
[passenger skips reading this to focus on the buffet listing]
Mystery rouge wave didn’t happen.
There are lots of waves in the ocean.
They aren’t necessarily going in the same direction or at the same speed.
And waves are just that, waves. From a mean sea level, they have a peak and a troph. And for a 1 foot wave ( from mean sea level) it is 2 feet from peak to troph.
Add in other waves from other directions, even slightly different speeds, etc. And you can get superimposition of one wave at a particular height, with another, of a different height, speed direction.
And don’t discount that 2x of the peak to troph around mean sea level.
They are weird. They literally come out of nowhere.
And I don’t know just how the tourist was killed. Could have been jolted sideways and clonked his head on a steel bulkhead, or something.
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