Cloaking Technology Could Protect Offshore Rigs From Destructive Waves 56
cylonlover writes "Recent years have seen much progress in the development of invisibility cloaks which bend light around an object so it can't be seen, but can the same principles be applied to ocean waves that are strong enough to smash steel and concrete? That's the aim of Reza Alam's underwater 'invisibility cloak.' The assistant professor of mechanical engineering at the University of California, Berkeley, recently outlined how to use variations of density in ocean water to cloak floating objects from dangerous surface waves."
Re: (Score:1)
Aha. Care to share your credentials in fluid dynamics with the rest of the class Mr AC...?
Re:Might look good in a wave tank (Score:5, Informative)
No credentials other than 5 years of sea duty with the US Navy. A few months of that time were spent on "rough seas". At least a month of that were on seas that came close to those described in "The Perfect Storm" - often exceeding 60 feet, and at times exceeding 80 feet. No hundred foot seas for me, 80 was enough.
Now - are you ready for it?
Neither the waves nor the swells are very random. I don't believe that anyone can predict them with very much accuracy, as of now, but they are generally predictable. Chop is another matter, entirely. If there is any way to predict chop, I can't imagine what it is. But, chop has very little energy, and has almost zero effect on the stability of a ship, or any other large platform.
I highly doubt the effectiveness of this cloaking device, but if it is somehow capable of mitigating some of the water's force, then we can and will develop the software to better predict the actions of swells and waves.
That said - I don't believe any software will be able to take rogues into account. They are named rogues, because they run counter to prevailing seas, seemingly at random.
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I, however, do know about oceanography. And I know that calling the technology a "cloak" is a joke, it's simply interference. I haven't even taken Physics III and I understand the principles behind the technology. A typical rig has water velocity sensors looking horizontally outward close to the surface and downward on the drillin' axis. Such a "cloak" would be pointless because the rig is pragmatically a fixed structure and bad conditions above are the same as bad conditions below. In short, if shit too wi
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Fair nuff. But are there wave-based 'storms' well below the surface anyway? Apart from regular ocean currents, I thought I read that once you get a few metres down it's all status quo. Certainly as far as temperatures are concerned, which don't vary by more than 3 degrees or so once you get 3 or more metres under the surface, same depth vs depth, all the way from the equator to the poles. But what I read may have been full of shit.
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It appears that the 'cloaking device' would create impulses in the water that would null out at least part of the big nasty surface wave. To do this, it has to be coupled to the surface - otherwise no energy would get imparted.
The physics of wave amplification and cancellation are well established. I imagine that we have the technology to look at the waves coming at the rig, figure out the waveforms and come up with 'counter' waveforms. I'm having problems, however, figuring out where he is going to get
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I'm having problems, however, figuring out where he is going to get the energy to make the counter waves.
Energy, oil companies? Not a problem. Do you know how much energy it takes to pull a several miles drill string out of the ground when comes the time to change the drill bit? Hint: the hook that grabs the string is 15 to 25 tons on triple rigs (they stack 3 pipes on the derrick when pulling out, to make things go faster).
Now, do you know how much energy it takes to drive and the size of the pumps that push drilll fluid inside the drill string ?
In order of magnitude, cost efficiently speaking, I think it wou
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Furthermore, once the hole(s) in production, just use the natural gas coming out to power the "cloaking" device instead of burning it. That's the big flame you see on production platforms. They just waste it because it is to risky and not efficient (money wise) to store.
Hell, on production platforms where not much natural gas comes out, just use crude oil. Some super tanker boats run on crude oil so energy sources do not seem like a show stopper anyway.
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Nothing a few caterpillar generators can't do. Platforms have more than that available, they could just stop drilling and divert the power to counter-measures. :
http://slashdot.org/comments.pl?sid=3268803&cid=42071527 [slashdot.org]
http://www.google.ca/url?sa=t&rct=j&q=how+many+MW+on+a+diesel+elecric+drill+rig&source=web&cd=8&ved=0CHcQFjAH&url=http%3A%2F%2Fwww.cat.com%2Fcda%2Ffiles%2F3072695%2F7%2FGP11PR6.docx&ei=YievULnYJOrg0gGSkoHACw&usg=AFQjCNEn8gYamAjnWDX7SF9lpTpqpFljpw [google.ca]
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The diesel electric rig I used to work on had indeed 10 of them and it was a plain on land rig. That rig wasn't the biggest either. Bigger = able to go deeper.
Also, as another poster as noted, if you read TFA, that kind of power might not be needed at all. The "cloaking" device would be installed at the bottom of the ocean and it is not clear how much power it would require if any...
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I know the pics show the device on the bottom but seemingly that would work only for shallow water rigs and not for the deeper platforms. Still would need large amounts of power (I guess). And dealing with a 100 MW power plant (or the output of same) on the bottom of the ocean is a pretty big engineering challenge.
Nice to have some real numbers and a better diagram.....
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I don't see why people are assuming this would need a ton of power. How much power does a mirror consume, or a quarter-wave-plate? Changing the impedance of the water locally, or otherwise changin its dynamics, so that the wave energy takes a less destructive form as it passes the rig doesn't require power on the scale of the waves.
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Do you know how much energy it takes to pull a several miles drill string out of the ground when comes the time to change the drill bit?
No, do you?
Now, do you know how much energy it takes to drive and the size of the pumps that push drilll fluid inside the drill string ?
No, do you?
In order of magnitude, cost efficiently speaking, I think it would be feasible.
Based on what numbers, or is this just a hunch?
All of this may be moot anyway, since I don't see anything in the article about energy having to be expended, except in the initial construction of seabed shapes.
He found that by placing a corrugated or wavy pattern tuned to particular wavelength on the seabed it would cause surface waves to temporarily become internal waves.
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Good point, I never said that kind of energy was required. I just wrote that it was available to oil platforms ;-)
http://slashdot.org/comments.pl?sid=3268803&cid=42071753 [slashdot.org]
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TFA states that no, they won't be creating impulses in the water. Instead, they noticed that
a. waves can travel on the surface, or at the thermocline.
b. waves interact with and can be influenced by the seafloor.
They propose to shape the seafloor so that the waves move from the surface to the thermocline. This means the wave is no longer visible at the sea surface.
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Sea conditions are felt more than a "few meters down". Anecdotal evidence suggests that a storm's actions can be felt at 500 feet, and really severe storms even further. I've never been underway in a sub, so I have no firsthand knowledge. Bubble heads will tell you that they dive when the seas are rough. The rougher the seas, the deeper they want to dive.
I don't think any storms are likely to be felt past 500 meters, or yards.
Re:Sound Studios (Score:2)
Music tends to produce a pretty random array of waves, yet I've seen active acoustic stuff (bass traps) in studios that fixed all the deleterious waves that would ruin the recording. Same principles at work, methinks.
Maths FTW!
Will need... (Score:2)
Just sayin'
The utility of math is fascinating... (Score:5, Informative)
I am perpetually impressed by how useful mathematics derived from a few abstract axioms can actually be in modelling the real world. Further, it is always fascinating to see the strange overlaps where a single mathematical abstraction proves useful in the examination of two seemingly unrelated phenomena...
It is apparently so; but the idea that waves made of seawater and 'waves' that function as models of certain aspects of the behavior of electromagnetic radiation is always deeply surprising.
Re:The utility of math is fascinating... (Score:4, Interesting)
There's an essay by Eugene Wigner about exactly that topic:
The Unreasonable Effectiveness of Mathematics in the Natural Sciences [dartmouth.edu]
Must be something in the water (Score:1)
Someone getting an early jump on April 1st?
Is it Romulan? (Score:1)
Did they get this cloaking technology from the Romulans?
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Interesting (Score:4, Informative)
The last one I saw was this: http://www.newscientist.com/article/dn14829 [newscientist.com]
and: http://discovermagazine.com/2012/jul-aug/06-how-to-make-anything-disappear [discovermagazine.com]
Does this invisibility cloak? (Score:3)
Ha! You can't see me! (Score:2)
Well, it would probably just do as much good.
Interesting idea, but how would you put it to use? (Score:1)
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As I understand, to generate that cloak you need to create/modify underwater layers by changing salinity or temperature or direction.
You misunderstand:
He found that by placing a corrugated or wavy pattern tuned to particular wavelength on the seabed it would cause surface waves to temporarily become internal waves.
The two layers of water are a natural phenomenon which allow the waves to be transferred underwater.
Re:Interesting idea (Score:1)
He found that by placing a corrugated or wavy pattern tuned to particular wavelength on the seabed it would cause surface waves to temporarily become internal waves.
The two layers of water are a natural phenomenon which allow the waves to be transferred underwater.
"Tuned to particular wavelength..." how is that a natural phenomenon?
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I have not RTFA because that's how it is but there's another fine way to change the density of water, you inject air. They can store air pressure in a weighted cylinder, water columns... etc etc
other way around (Score:5, Funny)
Oil rigs are pretty good at exploding on their own without huge waves. we need something to cloak the ocean (and the atmosphere) from from the effects of oil rigs. soviet russia you're our only hope.
Explains the missing island? (Score:3)
Those ocean researchers should really check whether Sandy Island [slashdot.org] is not actually covered in an invisibility cloak.
"Cloaking" (Score:2)
The soon to be over used buzz word of 2013..
shield, not cloak (Score:2)
While the technology might have the same basis as these cloaking efforts, this should more properly be described as "shields".
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Yeah, everyone likes "invisibility cloak," but I don't see it.
--Greg :-)
wait... if the waves cannot see the oil rig (Score:2)
They should apply it to cloaking cars. Then there'll be no accidents. Very practical.
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Good grief. Is everyone suffering from toomuchturkey stupidity today?
You muck with the waves coming in so as to force local interference effects. If you did it right, there's a node at the platform and bigger waves somewhere else that don't affect the platform.
Sheesh.
in other news: "bring the oil barrels!" 150 y ago? (Score:2)
Long, long ago when I was young, I used to read adventure tales.
All those that happened at sea had the mandatory storm scene of course -- and each time, classically, the pirate captain (or whatever novel hero) suddenly decided to drop oil on the terrible sea, which by this way turned way cooler.
Mind you, I even tried this myself!
Now, of course, you need, and will waste, oil. I understand it's not fashion nowadays...
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There was a SciAm article about this mentioned on /. in the last decade or so, finding some merit in altering water composition locally to create locally calmer seas.
This approach alters local impedence through the shape of the ocean floor, not the composition of the water, but it's the same basic idea.
Ogg say Need Gauusian diffusion resonance window (Score:2)
Not single pure damping frequency of circular ripples on ocean floor as depicted in simple diagram. Ogg say using single frequency like silly noise cancellation experiment where complex wave beat at edges of cancelling cone to make frog whisper artifact or low frequency beat that make heavy furniture walk around room and make dust bunny dance.
Ogg say use simulation to find most potentially harmful frequencies to oil platform and plot bell curve around them and make concentric patterns of bumps on sea floor
Slashdot Luddites (Score:3)
As typically happens here on Slashdot, most of the comments deliberately ignore the technical content and make bad irrelevant jokes and/or trash the researcher for being stupid. The person who wrote the original paper is clearly a very intelligent and accomplished academic and doesn't rate this kind of mindless attack. You don't get on the faculty at UC Berkeley by being less then competent.
The "cloaking" description was clearly written by the semi-literate incompetent hack who wrote the fluff piece that quoted the original research. They were trying to tie this research into the recent publicity on electromagnetic cloaking with microwaves and did a very bad job. Any criticism or analysis based on the idea of cloaking is obviously bogus and irrelevant.
From what I could glean from the garbled information, this technique is applicable for the conditions found in deep water oil drilling platforms. It seems that it could decrease the energy of large waves by channeling some of their energy into the water density boundary layer below the rig, providing an extra margin of protection. I doubt that it would diminish waves at all frequencies, but it would be tuned for the most destructive energy band. If it is practical it would be very useful.
Ogg is dumber then a box of rocks. If dumping a bunch of random sized rocks on the ocean floor would protect an oil rig then they would already be doing it. These things are so expensive that if this worked it would be cheap insurance and standard to the industry. To the best of my knowledge dumping rocks is done in shallow water to protect coastlines and harbors, not in deep water. Even if Ogg knows how to spell "Gaussian harmonic" that doesn't mean he is refuting the content of the academic paper. The dumb description just says "ripples", which could actually be a structure like Ogg described. Ogg is throwing stones at a straw man. Ogg's critique is at the same level as a chimpanzee throwing it's shit at something, and has a similar intellectual content.