My last G+ post reported this:
Something out there kills about one oceangoing ship a week.
It is probably freakishly large waves – well outside the ranges predicted by simple modeling of fluid dynamics and used to set required force-tolerance levels in ship design. Turns out these can be produced by nonlinear interactions in which one crest in a wave train steals energy from its neighbors.
Much more in the video.
So go watch the video – this BBC documentary from 2002 on Rogue Waves. It’s worth your time, and you’ll learn some interesting physics.
As I’m watching, I’m thinking that the really interesting word they’re not using is “soliton”. And then, doing some followup, I learn two things: the solutions to the nonlinear Schrödinger equation that describe rogue waves are labeled “Peregrine solitons”, despite not actually having the non-dissipative property of your classical soliton; and it is now believed that the S.S. Edmund Fitzgerald was probably wrecked by a rogue wave back in ’75.
In a weird way this made it kind of personal for me. I used to joke, back when people knew who he was, that Gordon Lightfoot and I have exactly the same four-note singing range. It is a fact that anything he wrote I can cover effectively; I’ve sung and played The Wreck of the Edmund Fitzgerald many times.
So, I’m texting my friend Phil Salkie (he who taught me to solder, and my reference for the Tinker archetype of hacker) about this, and we started filking. And here’s what eventually came out: Wreck of the Edmund Fitzgerald, the science! version:
The lads in the crew saw that soliton come through
It stove in the hatches and coamings
Her hull broached and tore, she was spillin’ out ore
That rogue put an end to her roamings.
Does anyone know where the Gaussian goes
When the sea heights go all superlinear?
A Schrödinger wave for a watery grave
It’ll drown both the saint and the sinner.
That is all.
> the S.S. Edmund Fitzgerald was probably wrecked by a rogue wave back in ’75
Perhaps, but I still don’t think we can rule out an attack by the rare Lake Superior Sperm Whale.
> Does anyone know where the Gaussian goes
But it’s blatantly not a Gaussian. As soon as they showed the Linear Model p.d.f. and described it as “a bell curve”, I was screaming at the screen that it’s not a bell curve, it’s skewed; indeed, to me it looks more like a Boltzmann than any other distribution that comes readily to mind.
(Also, pop sci is always really frustrating. I can understand them not showing the equations, but they could at least describe the mechanism by which the wave “steals energy from its neighbours”.)
Nice filk though.
>But it’s blatantly not a Gaussian. As soon as they showed the Linear Model p.d.f. and described it as “a bell curve”, I was screaming at the screen that it’s not a bell curve, it’s skewed; indeed, to me it looks more like a Boltzmann than any other distribution that comes readily to mind.
I wasn’t sure enough of what I saw to dismiss the voiceover. It could have been a Boltzmann or the right tail of a Gaussian.
I note that the line could become “Does anyone know where the Boltzmann curve goes?” if we can verify that was the distribution in use.
As someone from that neck of the woods, that’s about the only song which made it into popular culture which reflects any aspect of life from around there. The result is that it’s pretty much impossible to forget who Gordon Lightfoot is.
>As someone from that neck of the woods, that’s about the only song which made it into popular culture which reflects any aspect of life from around there. The result is that it’s pretty much impossible to forget who Gordon Lightfoot is.
Then there’s that Canada thing. I get that Lightfoot is still a big deal north of the border, but he faded from view in the U.S. when the singer/songwriter boom of the 1970s petered out. I can remember being mildly disconcerted on realizing I could no longer impress girls by being able to sing his material accurately and, man, that was a long time ago.
Alas, a lot of his stuff has not aged well. Some of it has been Muzaked, which didn’t help his reputation – to anyone under 30 he’s the kind of MOR music you laugh at your parents for liking. At least in the U.S. Wreck of the Edmund Fitzgerald is his only track that still gets some respect, but it gets a lot. I think it’s generally regarded as a classic by anyone who cares about the folk ballad form even a little.
Sometimes genius is serendipitous. Bravo!
Oh, and Harry Chapin has the same effect on me from that era. Can’t think of anyone like them in current music.
A big deal up here indeed. He got a tribute album a while back:
OT but of interest: Drupal Contributors Threaten to Quit After a Developer is Banned for His Private Sex Life
A review (fairly recent) of maritime casualties is here:
While rogue waves do exist the causes of greatest portion of losses are the usual: stupidity, poor training, poor planning, neglect of equipment and vessel, unprofessional and/or incompetent crews.
>While rogue waves do exist the causes of greatest portion of losses are the usual: stupidity, poor training, poor planning, neglect of equipment and vessel, unprofessional and/or incompetent crews.
You may well be right, but it isn’t possible to deduce that from the data they present. It doesn’t get deep enough into etiology.
I have to concur with one point of Mr. Cree, the mechanism of energy transfer is missing. As such they are only evaluating a signal which would be OK for control systems, but they also need to find the basic physical energy transfer mechanism (pressure differences? Friction? Resonance?)
It should be possible to create rogue waves in a lab experiment if the wave equation is known.
>It should be possible to create rogue waves in a lab experiment if the wave equation is known
It is. The Wikipedia article on Rogue Waves notes that they have been created in a water tank.
Don’t know if it was a rogue wave, the waves that were recorded that night were large enough to have a trough that would bring the Six Fathom Shoal shallow enough for the E.F. to hit. A rogue wave would bring even more to the E.F.’s bottom into contact with the shoal.
A few years ago, I worked with a crewman who was on the Arthur M. Anderson that night, he said it was bad out there and for him to say bad was telling. The sinking was probably a little bit of everything, a real Black Swan event.
I saw a video of one of the water tank experiments. The moment the rogue climbs up it looks as if it was alive, just like a good CGI animation. Then it crashes into the end barrier of the tank, goes up and breaks a hole into the roof of the building. Scary.
Who said math nerds were boring? You just added another stanza to the longest (lyrical) song in the English language and it’s actually, factually correct.