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Faster Than Supersonic Travel - Underwater
waimate writes "This fascinating article describes a scheme devised by the Soviet Union for superfast underwater travel - faster than Concorde. The idea is to use Cavitation - an effect usually the enemy of marine architects, and turn it to an advantage, creating vessels (initially torpedoes) encased in a bubble of vacuum and powered by rockets. All under the water. Watch out for that mullet !"
Incidentally, being hit at close range by a supersonic shock in air will kill a human. So you can imagine what this will do. Both v_c and isothermal compressibility are much higher for water.
I think he means when corporations buy patents and then not use them or let anyone else use them just so they won't have competition. Take my 14 year-old Kuschall manual wheelchair. It has a revolutionary folding mechanism that no other wheelchair used and won't use again until the patent expires. Everest & Jennings (which is bankrupt now) bought the designs from the Swedish wheelchair maker just to keep others from using that mechanism. It's now the year 2000 and all the foldable manual chair makers still use the same folding mechanism that's been in use for over 50 years. I just bought a new Invacare brand lightweight manual chair and it too uses the ancient folding design. Wow, that's great progress and we owe it all to corporations. If a device to remove hydrogen from gasoline didn't exist, all the oil companies would buy out any technology advancements in fuel cells to slow down progress. I am glad using gasoline in a fuel cell doesn't polute as burning it does. At least that's something.
Hmmm I think this could probabely cause another problem, but probabely I am wrong. You can't just travel trough water, the water must be moved somewhere. When you travel at such high speed the water must be moved somewhere very fast and water isn't very much compressable. So when one of these power submarines get near a shore they could produce some sort of artificial tsunamis.
The shockwave effect is much stronger in liquid than in air. I once saw someone first shoot a Bullet into an empty Barrel and a water filled Barrel. The empty Barrel just got a small hole, but the filled Barrel was completely blown apart.
- Yasa
Either you know a hell of a lot more about this than given in the relatively short blurb of the story, or you've gotta be psychic.
After all, you, SOMEHOW know that this thing will have to give a sufficient shockwave to kill the 'billions' of fishes, without knowing how strong the shockwave is, how fast it dissipates in water, and what animals will be affected (and how).
(Just as a random question, how many bacteria, birds, floating spiders, plants, etc, are killed in every shuttle launch. You're psychic ass MUST be able to answer this.)
You're either psychic, or spouting bullshit. Which one is it?
Why not just send a few of those torpedoes through first? That should clear things out...
Fluids are fluids, but some fluids support the weight of vehicles better :)
--Matthew
I remember stories about farmers complaining that their cows gave sour milk because of being exposed to the sonic booms -
if it ain't broke, then fix it 'till it is!
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
No, it was a caterpillar drive.
And the big flaw in the technology (besides the extremely low speed), is that a magnet of the size required to do the job would create one -hell- of a blip on magnetic sensors. Such sensors are used to detect the disturbances in the magnetic fields of the Earth caused by extremely large ships.
So basically, even if they can't hear you...they still know where you are.
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- Kate
"DNA is life. The rest is just translation."
any form of combustion forms nitrous oxides as a result. jet engines iirc are more notiorious than most (there being no particularly good way to tack a catalytic converter on the back of a jet engine, for rather obvious reasons) nitrous oxides are one of the many gases that are, or were at one time, suspected of being unfriendly to the ozone. while this is a minor issue for normal airliners, it is a much more hotly debated issue for the concorde (and any other high altitude jet aircraft) as they fly in the altitude range where these ozone depleting gases can do the most damage.
so yes, it's basically just a function of it's burning fuel, except that it's burning fuel at the altitude where it could potentially be most hazardous. i don't recall if this was ever proven or not, however.
If I don't put anything here, will anyone recognize me anymore?
"who wants to sit in a craft as it is fired from a gun, or risk getting stranded in the middle of the ocean if it slows down too much?"
This has to be one of the stupidest things I've read in a scientific article. HELLO!!!
Think about airplanes. Hey, what happens if *they* slow down too much? Ever heard of stall speed? Hey, if this sucker slows down, and loses it's ability to supercavitate, as long as it doesn't hit too much turbulence, then at least with a minimum of equipment it'd simply maintain ballast or float up. Beats dropping into the ocean from 30,000 feet in that Concorde!
And if someone mentions the fact that going that fast is dangerous due to turbulence, go look up what happened on the first dozen or so style of planes when they went supersonic. If the leading and trailing edges are incorrectly engineered, they create 'ripples' of compression and vapors that can develop un-equal forces on the plane's control surfaces, literally throwing it into a spin or ripping it into pieces. It's an engineering issue, sure, but so was Mach in the air.
I have read articles by 'experts' of the time saying man would never go above 50 miles an hour in an open vehicle as the 'air pressure' would prevent him from breathing. *sheesh*
That huge cost difference is due to the price of fuel for the Concorde. During design, they didn't expect the oil crises of the 70's, nor how much fuel the final aircraft was going to consume for how little payload/few passengers it can carry.
The environmental stuff you are talking about was no minor thing...the noise of the aircraft is tremendous even at slow speeds. (You have to remember, by the time that the Concorde could actually do commercial service (1976 or so) Boeing had already given up on making its own supersonic aircraft.) So the Concorde was prohibited to come into the US, at the request of communities surrounding the airports. I forgot how they fixed that problem, I think it was some sorta special agreement that allowed more routes to Europe for US based carriers.
Actually, I would think at these speeds, a dolphin, or whale, or any large mammal for that matter, as well as debris, pieces of shell, metal, etc. would be catastophic for the "Sub". Moving at that speed, a small piece of metal, relatively stationary compared to the "sub" would destroy the sub if it somehow was forced into the bubble, however, most surrounding creatures shouldn't effect it, seeing as the force on the outside of the bubble should literlly clear away anything in it's path.
"God is REAL
Imagine flying around on supercavitating, underwater "jetskis". What fun! Quick, to the patent office!
I assume if you've got a propulsion powerful enough to push that much water out of the way, lift is the least of your worries. Just angle the jet downward a bit. I imagine you could do that by modifying the shape or attitude of the tip of the craft. Still, the article mentioned wings (only the tips of which would be touching water) as a method of steering so they could use that for lift as well. I guess this is simpler than steering with the tip because of the enormous preassure on it.
--
Fuck the system? Nah, you might catch something.
Strikes me that if you drive into anything that collapses (or even significantly wobbles) your cava-bubble, you're going to plough into plain ordinary water at supersonic speed, and decelerate pretty sharpish. Even assuming the hull doesn't smash into confetti, the passengers will be salsa on the forward bulkhead.
They're already doing things to help create the shock wave in front of the craft. Basically it involves shooting a stream of plasma ahead of the cone. Plasma super-heats the air, causes a shockwave, shockwave creates a "hole" of low-pressure for the craft to pass through. Nose cone still critical though. :)
If such a rocket could be built, it would seem to me that using it to either
1) move stuff up to space
or
2) move stuff around the planet, via a nice high (ballastic) trajectory
would be a much more worthwhile use of it.
"I can only show you Linux... you're the one who has to read the man pages."
I'd be willing to bet that they have a good handle on how light is refracted by sea water and can compensate for it. Otherwise, all you'd have to do is fire one round, watch how far it misses by, and then compensate with a second round. Easy.
Work is for people who lack the imagination to play.
I don't think so, otherwise they would've been able to reach their destination in mere hours instead of the damn long time it took them.
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Insert Witty Sig Here
Float to the surface, and start up those rockets. Keep flying/bouncing until there is speed enough, then dive.
These things move faster than the speed of sound in water. So sonar & similiar eqipment can't see an incoming shkval at all before it hits.
Taking a look at the trail after being hit may not be that interesting.
Interesting - I think the only way it could be done in air (that you are suggesting that is) is to have the bubble be a pure vaccum so there is now drag. But I guess you hadn't thought of the fact that a pure vaccuum provides no lift. So you need air. This is not the same as underwater, in this case, since they are being launched and just going and going - under water you can have the same bouyancy as the surrounding material, which is tough in a plane. So the only feasible way would be to somehow launch a craft at such high speeds that the lack of lift would not matter - and this is essentially putting the craft into orbit. And I still don't know how you would get a pure and complete vaccuum around the craft.
-Leo
That is true, but it still does not explain what the surrounding medium would be - a pure vaccuum? Or something else? The reason bubbles hold underwate is because if the internal surface tension on the barrier between the water and the air pulled out of the water. Last time I checked, there was not much tension on the surface of a vaccuum. In fact, the Van-der-Waals force between molecules of air is so much less than that of water that I doubt any type of bubble like that could hold unless you created a traditional bubble - with a medium that holds together on the boundary (the skin of a soap bubble, the soap itself).
But it's all speculation anyway - without a good flight plan they're screwed from the start.
-Leo
Dude, try thinking. The water is vaporized. If you do it in air, you "vaporize the air?" No, it's already a vapor - so use a vacuum smart guy.
-Leo
This sounds like a really cool technology - however it has quite a ways to go before it might be considered for commercial use. As people already have mentioned (I'm sure) the environmental impact might be significant due to the great speed. Also, any number of things could cause the vaccuum around the vessel to dissipate (watch out for the seaweed) and drag the ship down. But these bubbles have very interesting physical properties. not just the bubbles to encapsulate the ship, but just bubbles in general (in a liquid, that is). Their ill effects were obviously noted when props on ships started to corrode and such. Also, when electroforming, bubbles can help agitate the solution for quicker ion dispersion, but if the bubbles are near the surface being electroformed then the bubbles cause disuniformity.
Anyway, bubbles are just fun. Expecially Soap bubbles.
-Leo
i am not a areospace engineer in anyway, but can't this technology be used to help spacecraft on re-entry? if we only had to worry about the nose burning up, that would seem to be a lot easier.
I don't think these are going to disappear beneath the sea. Even a conventional torpedo leaves a bubble trail. Imagine the bubble trail left by such a craft.
----------------------------------------------
the pun is mightier than the sword
I do see some problems with it replacing airlines. Although 30 minutes from Minneapolis to Florida would be nice to achieve, I suspect people near the surface of the Mississippi River would not be particularly fond of the technology.
It may have not been clear in the movie, but the book explained it was more of an electromagnetic jet. Water traveling through a tube was accelerated by magnetic fields, moving the submarine much more quietly than allowed by propellers. Silence is loved by, well, the silent service.
With directional propulsion, it'll turn faster & brake faster out of harms way than most aircrafts.
I see. In the future, the "fasten seatbelts" sign will mean dolphins ahead instead of a thunderstorm.
I wonder what the effect on the passengers on a craft like this will be when they are exposed to several Gs.
If J.K.R wrote Windows: Puteulanus fenestra mortalis!
Assuming supersonic travel underwater produces the same kind of shock waves ("sonic booms") that air travel does, damage to the hearing of marine mammals could be extensive.
Not to forget that underwater shockwaves are a lot more powerful than those in air. I'd expect that a supersonic underwater veichle(sp?) would have a nice large death-zone.
If J.K.R wrote Windows: Puteulanus fenestra mortalis!
Okay, the technology is called "super-cavatation" due to the bubble of water vapor that surrounds the craft, and that it is this bubble which produces the low drag effect.
So, any system which can create the bubble would work. It just so happens they discovered the effect due to a shock wave, but I don't see why some sort of method to artificially create the bubble (sans high velocity) couldn't be developed.
A similar concept seems to be the aerospike engine, where plasma is generated in the direction of travel to reduce drag. Same principle, different technology (air travel).
So the effect may scale up quite nicely to larger craft. Time and experimentation will tell.
Positive steering is a problem only if velocity cannot drop below a certain level. Find a way to keep the bubble going at low speeds, and turning becomes more managable.
More general navigation issues: Bubbles make noise. Lots of noise, from bass to ultrasonic. Normally, this would rule out sonar. Except that, at least a small portion of the leading edge of the craft will be in contact with water. So, pack your sonar array into that area (yes, probably beyond our current tech). It would give you a small viewing angle, but it's better than nothing.
This is all just from the hip reasoning, and almost certainly has holes in it, but I'm prompted by the constant negativity I continually see when new technologies are announced. I mean, c'mon, where's your sense of wonder? Imagine what might be done with this, play with it, see what comes up.
"Avast! Prepare for the rodgering!" THWACK! "Arrr.. me nards.."
The reason I wonder is that this is very nearly the same thinking that's used in missiles- an ICBM has a rounder nose, too, not a sharp point. Just as a diver doesn't cleave into the water, but rather punches his way, so too do missiles.
You would have thought the Navy would have been thinking about this since the 60's.
Interesting idea, though, but I think moreso for the mine-killing aspect of it.
stored on computers from birth to the grave
yup. thats what i thought too. of course, saturn Vs engines produced as much thrust as a small nuclear weapon detonating. if you use rockets, you have high energy densities...250GW isnt too much for a solid rocket booster.
(9) If people are interested in travelling on submarines, why don't we have commercial submarines now?
We do. I have been on a commercial submarine that was used for siteseeing purposes. A bit scary when they lock the hatch and you wonder if the pilot progressed from pleasure crusers. It was well worth it though. However, I don't think you would be doing much siteseeing at mach 1 so I guess you mean for travel. That I grant you is unlikely.
Bob.
(PS, wasn't there a story on slashdot about some company selling luxury submarines to budding Blofelds?)
Anyone remember what shape the silver thing in Flight of the Navigator changed into before it went underwater. I only ask because I wondered how scientifically accurate they were being.
:-)
Bob.
Supersonic is just faster than the speed of sound, so you can't really go faster than supersonic. There's no upper bound on how fast supersonic is. =)
Well I suspect Minnesota natives in 40 below weather in the dead of winter would be VERY fond of the technology, doncha know?
"Travelin' though hyperspace ain't like dustin' crops, kid! You could hit an asteroid field or a supernova and that'd end your trip real quick."
-- Han Solo
heard of this too.. apparently the Waterbird (I don't remember the name, so I'll assume the previous poster was correct) relied heavily on the wing-in-ground effect. The principle is that a wing with a large surface-are created an aircushion below the plane to provide the lift, which turns out to be quite efficient, more efficient than 'pure' flight, leaving more power for propulsion. The russian craft was used for cargo. Other 'planes' that use this are a.o. the Flarecraft.
I think the flarecraft doesn't even count as an aeroplane, but as a ship because it can't get much higher than 10m from the surface (usually water, but like a hovercraft this isn't necessary)
//rdj
No one can understand the truth until he drinks of coffee's frothy goodness.
--Sheikh Abd-Al-Kadir, 1587
I am like 100% certain that by "supersonic" they mean faster than the speed of sound in air. Sound travels about 5x as fast in water.
Now, I'm not saying the rest of this proposition suddenly is reasonable or anything. But THIS particualar problem is not one, though.
Trees can't go dancing
So do them a big favor
Pretend dancing stinks!
Flight of the Navigator? Wow, wasn't that a Disney movie from like 1986? Huh. That was my kind chick, the one who helped him escape from NASA. My first crush.
... things travelling under the ocean at impossible speeds. Although I do believe in UFOs, I think this may explain those "sightings" as top secret black-projects by the Navy and such.
>> (2) Most of the marine life (including seaweed,
>> etc) stays relatively close to the surface.
>> Great, you say -- makee the thing travel
>> deeper to avoid skewering whales, etc.
>> Well, that'd be nice, but it's a *lot*
>> harder to cavitate at depth due to the
>> increased pressure (and reduced temperature) --
>> and the relationship is not a proportional one.
>> Besides being harder to cavitate in the first
>> place, it'd be harder to maintain the bubble
>> around the vehicle (because sea pressure
>> would be trying to collapse it).
>
> a compromise depth of around 40m should do the
> trick.
how are you going to stay on 40m?
if you're travelling at some 500km/h speed,
it's about 150m/s.
if your direction is going only 1% too up or
too down, you will still end up on the surface
or be twice as deep in 30 seconds.
And, while your blind, you don't know your
direction and depth very presicely,
(conventional depth meter wont work in a bubble)
you may even not know your going too up until
you find yourself flying ten meters above the surface.
And, even if you knew your direction is too up or too down, how do you turn in the bubble?
There is also one very big problem:
fuel capasity.
The russioan torpedo runs only few, maybe few
tens of kilometers.
And the engine and fual already take very big
part of it.
To use it on longer (>100km) distances,
over 100% of the mass of the sub would have be
fuel. Or then we need multi-phase rockets,
just like on space rockets. And that's
_very_ expensive, as the payload is usually
about 1%or less of the mass of the whole rocket
Airlines out of buisiness? If I want to go from New York to Chicago how would I do it on a submarine? ;)
Wasn't a cavitation drive the super-secret technology that the Red October was supposed to have in Tom Clancy's novel "The Hunt for the Red October"?
I have saved some of my Starcraft replays here
Like the article said, who wants to be shot out from a cannon? The article didn't mention stopping though-- as soon as you slow down to a critical speed and the bubble collapses, all the drag kicks in and you may as well be hitting a wall of rock. Ouch!!
So, how about we don't slow down under water. Assuming the steering thing is figured out, we could just pitch up, fly out of the water, and then use parachutes. Of course the parachutes would tear apart at that speed, so maybe it should deploy wings instead. Plus, it would be the first vehicle that travels underwater and flies.
-CausticPuppy "Of all the people I know, you're certainly one of them." -Somebody I don't know
Any living organism caught by the shock front from this thing is going to be jelly.
Blasting through hyperspace ain't like dusting crops boy!
- passion
It does kinda have similiarities in a way... I think the theorists writing for ST once explained a Warp field as a soap bubble that allows the ship to 'slip' through real space though...
we are all invisible unless we choose otherwise
Actually this could be an interesting idea for rockets to use to reach orbit... That is if it actually reduces teh amount of energy needed to cause that effect. If it doesn't do that their isn't much point.
we are all invisible unless we choose otherwise
Shine on, you crazy diamond.
Ohhh, the answer man... :o)
:o)
:o)
-> obviously, you'd put the eyes in orbit.
-> a compromise depth of around 40m should do the trick
-> You'd also have marked lanes under water, and numerous turn-off/breaking lanes to divert the vehicle from collisions. Or, you might have a few accidents per decade, as there isn't much activity at >30m beneath the surface
Okay, let's go with the theory that this has potential (you've blessed me with the spirit of trying to find solutions).
Are you aware of a technology that can detect hazards for this beast at a depth of 40m from space? I'm not. Magnetic anomally and/or synthetic aperture radar are the two closest candidates that I can think of. The depth is pushing it for both, and neither is very good at detecting non-metallic things (and yes, non-metallic things can be hazardous).
Are you aware of a technology that would allow a satellite to communicate with a supersonic submarine at 40m - with the bandwidth necessary to relay the needed information *before* it's needed, and not sometime after? Again, I'm not.
Just trying to be helpful by letting you know what needs to be on your "to-do" list.
otherwise, it is a straight shot across an ocean
Nothing is a straight shot anywhere. Rockets, planes, submarines, cars -- all have to make minor corrections during their travel. Oceans have currents, sometimes strong ones. Some sort of course correction would be essential.
The rockets work on powdered aluminum. so there will be an increase of aluminum oxide in the oceans, which isn't going to be much consiedring the VOLUME of the ocean.
The types of comments Green-Peacer's just love -- hell, it's a big ocean, who cares?
Aluminum oxide rockets don't just spit aluminum out their pooper -- there's a lot of chemical reactions going on.
Besides, solid fuel would not be a likely candidate for a reusable, commercial, human transport.
and so the engines would have to unleash more force? I don't see the problem here
Engines unleashing more force require more fuel. More fuel requires more storage capacity -- which requires a bigger vessel -- which requires more force...lather, rinse, repeat.
cost is defined by demand.
I'm talking cost of materials to make the thing work in the first place. Add to THAT whatever profit margin they can tack on based on demand.
I know what I'd choose
So I take it you're currently choosing the Concorde, right? That's only about 2-1/2 hours, isn't it?
-CP
The military kills sea critters all the time. Submarines are horrible offenders. Consider that the a certain-sub-model-which-will-remain-unnamed has a reactor surrounded by water to protect the crew from radiation. On 3 sides. The bottom is pretty much flush against the hull, since no crew members go below the reactor compartment anyhow.
End result: sick fishies if they swim too close to the bottom of the sub.
And while I'm at it... active sonar and noisemakers aren't exactly eco-friendly either. Neither are the 55 lb cans they shoot out the TDU to the bottom of the ocean.
*shrug*
SEAL
While a Concord may contribute to ozone depletion, the amount it causes would be very minor. Modern jet engines are actually turbofans, which are efficient and relatively clean.
Contrast that with, say, an F-15 flying at extremely high altitude. Afterburners dump raw fuel into the situation, which is very inefficient and dirty.
Even this isn't TOO terrible, compared to CFCs (which I hope everyone knows about by now). These chemicals destroy ozone, and cause a chain reaction while doing it. They are far worse than anything coming out the tailpipe of a jet.
Best regards,
SEAL
The reason Concorde and competitors is not in wide use may be because of Boeing and other members of the US aviation industry. When it first appeared, they tried to delay it until they could bring out something of their own. Their weapon was an early Environmental Impact Assessment. They ended up making themselves unable to do anything which aroused this much public hostility.
It's a bit like if Microsoft said that open Source is a bad thing and then finding that they can never take advantage of it. They would then be forced to write bloated closed source apps.
I'll see your Constitution and raise you a Queen.
Why refract? If the Laser is of the right wavelength and power, it will create superheated steam when it hits the water drilling a tunnel straight to the target. Before the tunnel has a chance to collapse shoot through it.
Did anybody do the math? Sounds like we will still be accelerating a large volume of fluid over a very short period of time and that takes a huge amount of energy. Oh wait a minute this isn't a cap it's a Borg mind slug nevermind.
Err... this is an idea driven by the military, right? The primary objective seems to be to make very fast torpedos which will be more effective at killing people. Frankly I don't think they will really give a damn if they kill a few fish or dolphins while they're on their way.
(Mind you the idea of an ecologically sound military is even more scary in a bizarre kind of way)
This Russian project sure sounds a lot like Tom Swift's Jetmarine!
I wonder how FreeCiv and Civilization (Civ) will handle this. Of course, there would be the Supercavitation discovery. But what kind of transportation and weapons would we be able to build? I envision a hydro-lift (think air-lift) and a Transport / Mother sub with supercavitated bullets and fighter subs with a Attack/Hits/Moves ratio similar to 50/10/20. And of course, that means you need a supercavitation port city improvement.
:)
Mmm... can't wait to play...
...I don't have enough faith to believe in the "big bang"...
Everyone is worried about the dolphins because they are the second most intelligent life form on earth, and we are the third.
No, he had it right. The mice are the cheese hackers, and they are first.
1. Get approximate co ordinates of enemy targets.
2. Launch nuclear missiles.
3. Run away, pray, etc, you are now a sitting duck.
Friends don't help friends install M$ junk.
Well darn, didn't go back and read this for a while... here goes: 20,000 HP is actually more than what is generated at the shaft by a number of soviet ballistic missile subs (18,000+ tons), which is capable of driving them roughly 30 knots. These boats are roughly 100 times the weight of a whale (usually 150 tons or less), which immediately points to a 100 fudge factor. Realistically, weight is really a poor means of comparing things here, though. More appropriately, we should consider displacement (vis your method), or correctly, surface area, velocity contour, and flow regime. Your calculations are using an absurd model, and the only reason that you are within 2 orders of magnitude is because of scaling.. If we considered minnows versus submarines using your model, this would be readily apparent. (and I'd imagine you'd have problems staying within 100x) Basically, you have treated a torpedo as a large pump. This is physically unreasonable because you are assuming travel normal to local gravity. (thus incurring no g*z losses). In reality, all of your losses are due to either viscous energy dissipation or friction. This is reasonably similar to the pre-Gallilean assumption that acceleration due to gravity increases with mass. The reason nobody realized that this model was so poor was that nobody tried an experiment with a 10 gram chunk of lead versus a 10000 kg chunk of lead; within the very limited region of their experiments, and with those pesky aerodynamic effects, the model looked reasonable. For the same reason, x and x^2 look similar in a limited range (say 0 to 1) -- you'll never be off by much. But extend this to a range of 0 to 1000, and now you're off by 3 orders of magnitude. I'm as big a fan of the 'back of the napkin' calculation as anybody, but please, *please* use appropriate models.
Consider a blue whale with a radius of 2m, going at a speed of 13.4 m/s (Fastest recorded peak speed). The amount of water this whale has to push aside is pi*(2m)^2*13.4m/s=168.4 m3/s
That's 168 tons of water per second. Now this water has to be pushed around at around 13.4 m/s too, which corresponds to a kinetic energy of 89.78 kJ/ton of water. Combining the two results gives us 15.1 MW of power required to move our whale.
This calculation is beyond approximate... It's absurd.
A 20,000 HP whale would be cool, but I'd imagine it could also do better than 30 knots. Unfortunately, your calculations need some basis in reality before they make any sort of reasonable approximation (even with a fudge factor of 100x).
Others have duly explained why your computation is basically nonapplicable to the situation, so in the future, please(!) make sure you use the appropriate physical principles before filling others' heads with misinformation.
For referential information on Blue Whales, check out: http://www.acsonline.org/factpack/bluewhl.htm
It doesn't matter - the noise from the cavitation will drown out any sonar reading. You are flying blind. BTW, a torpedo using this technology is great - if someone fires one like this, it will be easy to detect, and the noise from it will cover up your tracks completely. -moi
Imagine a vessel larger then most of todays super tankers, that travels faster then sound (making it faster then most(all?) comercial cargo plains) and does so UNDERWATER. No worries of being hit my storms, taking on water or capsizing in extreme waves, because its already underwater!
Shipping costs for shipments across the atlantic and pacific could drop to rates comparable to UPS ground from Maine to Arizona! Shipping time could drop from days and weeks to hours!
This is some really amazing stuff they are comming up with, I only hope humanity doesn't get screwed out of useful tech by corporations traping this in useless IP barriers.
NightHawk
Tyranny =Gov. choosing how much power to give the People.
But on the other hand, you're right about jet tailpipe products not being extremely harmful to the ozone layer... The nitric oxides produced combine with water vapor to produce acid rain, but are not (as far as I know) active against ozone.
--Fesh
--Fesh
Kill -9 'em all, let root@localhost sort 'em out.
--Fesh
--Fesh
Kill -9 'em all, let root@localhost sort 'em out.
A very large firecracker, equivalent in explosive force to some significant fraction of a stick of dynamite. I haven't seen one in years, although I understand they can be obtained in some of the United States.
--
Does this sound like a Star Trek warp drive field generator to anyone else, create a buble of subspace particles and achive the ability travel between different regions of real space at faster than light, but your bubble is constantly being generated and degraded from leading to tailing edge
Read my plan to save the Bengals
Releasing payload creates the same effect, but no current SAM or other air defense system can get a long enough read to lock and track the target.
I suspect that a solution (Ground Based Lasers, kamikaze patrol drones?) are being developed to drop our stealths.
Read my plan to save the Bengals
I could see it as a revenge weapon but it strikes me as not very effective. What bubble head (submariner) would want to put this on their boat knowing that it has little chance of getting the guy who attacked first. And if there was any doubt of where you were ... well you just runied it 'cause Shkval can't be used in a dog leg attack. Kind of like pinning a big Hear I am tag on your head.
If you think about it a bit further you may see some other uses like anti-shipping. If one Shkval equiped submarine gets close enough to let 10 - 20 of these buggers loose at a battle group well ... there will be lots of flaming datums. In the confusion you would have a chance to get away. It is was deployed on a diesel boat it would be pretty scary 'cause they are very quiet.
In Anti-Mine Warfare these buggers would be pretty powerful like what the folks at NUWC sated. Although that would probally have things like Shkval deployed from air and surface units and not sumbarines.
Then again, I could be all wet (no pun intended) the Soviets/Russians we the ones who devloped the Alfa, a very fast and very noisey submarine.
- tech_imp
Shoot! I thought I was the only one doing cavitation studies. It's a pretty neat process to observe. Granted my studies have not been at the level of 'supercavitation' I can only imagine the flowrate needed to produce a cavity large enough to enclose an entire airfoil. Does anyone know of the energy required to release the air from the water? I've observed that at small deltas in pressure at and at flowrates as small at 15 gal/min small bubbles can collect on the rough cavities of small air foils, while smoother ones fail to yield the same results. Save the dolphins-take a plane.
she bent over, and all i could think was, "man..that's a nice shunt."
The speed of sound in water is about five times that in air. If you had read the article, you would have known this.
oh no! greenpeace will be gunning for my supersonic underwater F-16!!! That is quite a fight, an inflatable dinghy vs. a rocket sub with 20mm gattling guns. Oh, I'm only kidding, I know that political pressure can be an awesome deterrant...
On another note though, the term Aerospace no longer covers the full spectrum of high tech military presence. Nauto-Aero-Orbital-Space maybe? What will the proper term become?
And finally, imagine a hybrid fighter that can operate under water, in hypersonic dogfights in the air, VTOL hovering tank killer missions and orbital bombing capabilities all wrapped into one bad ass bird? It would also be all stealthed out and evil looking, designed to operate primarily at night in bad weather. oh, the sci-fi of it all!
I am not sure the commercial aspect is really the important feature of the transportation. One of the main aspects of submarines is that they are able to essentially disappear. It is extremely difficult to detect US submarines when they go quiet. Obviously the supercavitation drive would make a lot of noise coming and going, but that still gives you only a very general picture of where the sub is.
"Politics is for the moment, an equation lasts eternity" -A. Einstein
Question is: Do they care?
No. These are the same kind of people who make nuclear weapons (US and Russia). Killing some wild marine life is nothing to them when u consider that they don't care if the wipe out the entire planet's ecological system.
Its easy to state that, but the hard part is explaining why. I assume you are referring to my part about no use of it outside of high speed transit, and then offering it for probing the depths. If that is the case, feel free to see it that way. I do too. I meant to go off on another tangent, but wrote something else instead. So, yes, my argument is invalid. But the argument that is invalid only deals with potential applications, not with the danger to animals that the journalist himself mentioned.
Pax Digitalia
I understand now. thank you, I hadn't thought about the bullets that were developed. It would be useful.
Pax Digitalia
I don't see what part of the article supports your viewpoint, seeing as the article says 'Assuming it didn't hit a whale on the way, of course.' when referring to trans-atlantic crossing.
Besides, the practical applications of this dissipate as soon as you leave the field of high speed transit. What good is a cavitation bubble in clearing a mine? I could understand inducing a cavitation bubble to detonate the mine, but you would have to locate it first. This means that cavitation is as effective as standard methods of clearing mines.
If you wanted to come up with a good use of the technology, you should have mentioned deep sea exploration. If you want to reach the bottom of the Marinaras trench, you could fire a probe down to the depths, and use a cavitation bubble to protect it from the pressure. Only problem is, as soon as you stop moving quickly, youwould implode. Plus data transmission without a tether would be impossible. You would need to send the probe down, take surveillance at > mach 1.0, and return to the surface.
When I said 'Thank you, Russia' I was being sarcastic. (obviously) But I am sincere in saying that Russian technology is very interesting. They developed Ground Effect craft, Cavitation technology, good rifles, and good jets. I just wish we would think about the effects of flying around in our jets, driving around in our cars, or, now, diving in our jet subs.
Pax Digitalia
Cause it's sure to be a bitch. I'd like to drive one of these things, though. Ah, but not the first one, okay?
InstaPundit! Ahead of the Curve Since 30 Minutes Ago
Yes, it was designed to kill humans (a very bad goal, obviously), but that doesn't mean it can't be used to benefit humans instead. And if the technology is used to benefit humans, for instance, building a supersonic submarine for transoceanic travel (as an alternative to planes), wouldn't you be worried about it accidentally killing sea life?
BTW, the dolphin post was just a joke. It was meant to be laughed at, not criticized.
And I'm guessing mice are the 1st?
Well, we've already got these huge underwater "pipes". In fact, for years, they've been built nationwide, silently and underground, most notably around large population areas. The military could just use those pipes, or as they are known to civilians, "sewers".
Then again, there might be some soldiers who might protest being put into a little capsule and shot at great speeds through human waste.
Small potatoes make the steak look bigger.
'There's yet one more problem facing crewed, supercavitating craft, which no one appears to have an answer to. How will such a vehicle reach supercavitating speeds in the first place? After all, who wants to sit in a craft as it is fired from a gun'
Does anyone remember the name of the show from the 60's that had a flying sub? I want to say "20,000 leagues under the sea" but I might be getting it mixed up with Jules Verne's story.
I suppose slamming into the water at high speeds might be just as unpleasant as accelerating to those speeds in the water.
What about a vehicle shaped so that it starts out as a supercavitating hydrofoil but then lowers itself into the bubble gently? The hydrofoils would then jut out of the bubble once it is completely submerged becoming the control surfaces needed for steering.
While I would agree that environmental games by Boeing and others had much to do with the Concord never being more widely deployed, I belive that simple economics have more to do with the reason the Concord never took off. I also belive that before this supersonic underwater travel is widely adopted, that it will face at least the same or worse enviromental Impact Assessments.
/ spoffers.shtml
Most people that I know simply could not afford to pay 13 times as much, just to get to their destination 4? times as fast.
A round trip (London to NY)on the concord is $6500.
A round trip on some normal jet is less than $500.
http://www.britishairways.com/regional/usa/docs
Imagine a submarine positioning itself at a certin angle and direction and firing a supersonic bullet our of the bow. it explodes out of the water, travles 25+ miles through the air, and slames into sadam hussien's bedroom. :-)
Cool
Tsunimies are created by underwater earthquakes( or other like shockwaves). i don't think a freight liner sized vehicle is fesible, if only because it would destroy costal town with the tidal wave!(however, this might also be a good weapon)
you could use some kind of water ski to push aginst the inside of the bubble, maybe. this way the nose dosn't need all sorts of stearing stuff in it and can just be there to create the cavity. it would cause drag, but not as much as fins would. also, if the rocket continues to burn i don't know if the cavity can colapse, because the rocket puts so much force aginst the nose. the bubble might be disturbed by something like seaweed, might even set up wicked oscillations on the bubble surface, but as long as the rocket stays lit i think the cavity would be present. plus it might be posible to reinforce the cavity with the same trick they used with the rocket exhuast. it also seems like you could use a partial cavity just to reduce drag on a normal sub. for example, by releasing gas under the sub into a noch or groove they could ride on an "air slead".
i was thinking of this to, only in the ground a la subways. But the more i think about it, i don't know if you could build a tube that would stand up to the shockwaves and exhaust fumes of the vehicle. this would be doublely important for undersee tunnles becaues they might explode behind you from the shockwave!
I love puns.
- Wedg
Jake
Dating: while( 1 ){ call_girl(); get_rejected(); drink_40(); } return 0;
- Wedg
Jake
Dating: while( 1 ){ call_girl(); get_rejected(); drink_40(); } return 0;
I'm wondering why steer at all. Would this work on a train? Perhaps if it could be kept up to speed on a track of some kind? Maglev underwater?
joel
Such is the infinite Grace of Popeye.
Most commercial aircraft don't use GPS - they use ancient inertial nav, and it works well enough for them.
The speed of sound underwater is much, much, much faster than the speed of sound in air because water is more dense. This means that the molecules are closer together and therefore have to travel much less to push over the next molecule (sound). If you're going through a solid material, the same concept applies.
hlag
Doh! And just when I thought I had a legitimate non-trolling post for Slashdot. :)
If I'm not mistaken, drag is proportional to the SQUARE of an object's velocity, not the cube:
D = Cd * r * v^2 / 2 * A D = Drag Cd = Coefficient of drag r = rho (air density) v = velocity A = reference area
Ok, this is faster than the speed of sound in air... how fast does a sound wave travel in the sea? If it is faster than a sound wave will travel in the sea it cannot use sonar to "see" at all.
If voting were effective, it would be illegal by now.
With their blunted cone-shaped noses, the laser-targeted bullets will be fired from more than 350 metres above the water, travel 12 metres through it and still be able to zap a mine.
I hope they're shooting from straight above, otherwise refraction (of the laser going from air to water) will mess them up and they'll miss.
IANAP but it seems to me that steering could be at least aided by varying the nose which creates the cavitation.
The changes in the "bubble" and the resultant pressure changes of the vapor would provide an aerodynamic force capable of steering the craft.
What I want to know is with the tests they did, what were the effects on the surface?
--
Dyolf Knip
This would work well for torpedoes, but given that submarines 'see' by SONAR, and that the cavitation will completely screw that up - then they'll be 'flying blind', at high speeds. Not good.
Concorde flys at much higher altitudes than ordinary jet aircraft in order to reduce drag and skin heating. The claim is that, flying at such high altitudes, Concorde's emissions can reach the ionosphere and interfere with the formation of ozone. I don't know of any study which has confirmed this (but then again, I've haven't looked at all).
Well, when the military wants a weapon, i don't think they give too much thought to the environment. Just look at nukes!
Look at the neutron bomb. It was designed to be a weapon used when an invading army was coming at you, having limited range and minimal destruction (beyond the immediate blast area, only living organisms were damaged). It was to be used when a defender was seriously outgunned/outnumbered, and would be a response that could stop the invader without having to resort to heaving thermonuclear weapons at his cities. The no-nukes crowd went nuts, calling it a bomb designed to kill people while leaving their buildings and equipment intact (strictly true, but ignoring its intended use as a defensive weapon, not an offensive one). The enormous political pressure brought on the issue effectively killed the neutron bomb. So I disagree that whatever the military wants, it gets.
I know, I know, it's the engineer in me. I can't help myself...
None of the mammals of the family[?]
/. is totally unfathomable /. contributors so that only
Cetae have an external organ resembling an ear
or even an ear spot. I know, I've looked.
They don't have ear cannals nor do they
have a tinpanic membrane elaborated over
the cochlear cannal as an *interface* to
the outer world. Can you imagine the forces
that would be involved in a mile deep dive
for food.
Its not my intent to embarrass anybody,
there are many fine individuals who don't
know whales don't have eardrums,that are doing quality work in their respective fields.[[or I wouldn't have bothered with what would have
been an obvious point]
As what constitutes graciousness on
a webpage such as
to me. The fact that he's interested in such matters is his own commendation for which
I can neither add or detract. [Unlike a few
moderators who seem intent to trash the good
works of
a few dolphins can see it for political reason
known only to them & the people who they are
trying to impress]
Thank you for your interest.
|X|
Since Geo. Washington, the officers of
the Armed Forces have all been
Free Masons, which may be why
their Russian Brothers had our
troop movements before our men did
in Korea.
VA doctors have found neither
chemical or biological
justification for the Desert Storm
Syndrome. Perhaps our officers
are punishing our men for what
they did under orders. Symptoms
created with a MICROWAVE LASER.
Heeeheee...
Sounds like SeaQuest...
Many years ago the Russians had the 'WaterBird', a plane that skimmed the surface of the water. Supposedly on calm days it could go supersonic as well. In rough conditions the torpedoe type design of this vessel would allow travel while the 'WaterBird' would not.
I think the same way as the original AC, so here we go: Next time, try understanding an article while you're reading it. The following quote might have helped you: "An unpowered projectile, with a carefully designed flat nose and fired from an underwater gun, broke the sound barrier in water. That's nearly 5400 kilometres per hour--or 1.5 kilometres per second." And, moderators, if the parent post is "Interesting", I'd hate to see something you thought was boring.
nal 11
Does any of this sound like the flying subs out of X-Com 2?
I think they'll need Ion Drive Accelerators at least, and maybe some Magnetic Navigation, Alien Sub Constructions, and a load of Aqua Plastics to pull off anything very useful out of this...
The article made a technical mistake that is confusing people. Cavitation does not create a vacum. It pulls disolved air and/or water vapor out of the water. I haven't found a great explanation on the web, though some site get it right and some seem a bit misleading if you don't read carefully/completely. Good applied fluid dynamics books will get it right. You can watch the bubbles float up off of the propeller in submarine movies. That isn't because the boat is leaking.
It does not occur with sufficiently pure water. In addition to the disolved air, the amount of particulate impurities (dust) also has an effect. Apparently, like raindrops and ice, the bubbles like to have something to form from.
It still might be better than supersonic atmospheric flight, especially w.r.t. thermal characteristics. You have two interfaces to spread the heat disipation over, and water might carry away the excess heat better than air does. Also, if the cavity is in a more or less steady state, there is much less expansion and contraction going on. Even in air, the problems are most serious in the transonic regime where parts of the flow over the body are supersonic and parts aren't. The concord can turn off it's afterburners past mach 1.5 or so.
I suspect that the ICBM is more worried about lack of friction post reentry. Much like a bullet, except that ICBM may be worried about excess heat more than loosing speed. Just a guess though, if I actually knew, I probably wouldn't be allowed to talk about it :-)
In other words same problems as with modern aviation (most modern planes are incapable of flying with all of their engines shut). So the solution is well known - do not stop.
:-)), the danger of this is so low that they practice this regularly.
What planes do you speak about? Modern airliners glide as well as gliders from ca 1950. Modern airliners have glide slopes of about 1:30. Actually, about a week ago there was an emergency landing of an Airbus in vienna without power. Not one person was hurt during the landing. Some people who had short trouser burnt their legs when they slid down the emergency slides.
There was another accident where a Boeing lost power over the atlantic - it had to glide 100 miles to reach the shore.
Helicopters are also very good at "gliding" down without power (called autorotation). When done correctly (and the landing strip is near
How does this submarine navigate or see where it is going. Assuming this is travelling at above, or at least about the same as the speed as sound in water, then active sonar is useless, not to mention probably wouldn't pass through the inside of the bubble. This sub would probably be too damn lound to use passive sonar, and I really wouldn't want to depend on satellite navigation or anything like that.
Simply put, what good is a blind supersonic torpedo?
And god forbid you get too close to a coral reef! That's the problem with fast underwater travel - there are too many things to hit, at least compared to air travel.
Paranoids of the world, unite!
Fight hunger. Filet a politician and send him to a 3rd world country of your choice.
".. broke the sound barrier in water. That's nearly 5400 kilometres per hour--or 1.5 kilometres per second . [...]"
Perhaps its my poor understanding of the english languaje, but one thing is true: Sound doesn't travel at 1.5 Km/s. Lets see: 360 m/s = 0.36 Km/s = 1296 Km/h != 5400 Km/h (wow!)
Oops, forgot the fundamental rule of Science: all constants are variables
So, lets do it again: 1 Km ~= 1000 Km, say 250 m (aprox). So: 360 / 250 = 1.44 Km /s = 5184 Km/h which is aprox. equal to 5400.
hehehe
"2 is not equal to 3, even for large values of 2"
Yes. They could emit sound waves. But the craft would be traveling faster than sound. The craft would arrive at the obstacle before the sound. If a predefined lane of travel were kept clear by a series of sound-emitting buoys, however ... presuming that a sound could be tailored to repel creatures large enough to be hazardous to navigation. Sharks, etc. might not be repelled by sounds that repel dolphins and whales. Such a series of buoys might also have the effect of interfering with the migratory patterns of some marine fauna.
Won't they need to create an underwater whale whistle. I'd hate to crash into one of those.
Kate
_________________________ Visit me at http://pornforcomputers.com
Speed of sound in water. Thats 1.5 kilometers per second.
Fact: The denser the medium, the more energy needs to be spent for a certain speed.
If this thing's going to use rockets commercially, why not stick them on a 747 sized plane and send it on a ballistic path through near space? Travelling in a near vacuum needs bugger all energy for ridiculous speeds - a far more efficient use of resources.
Also - no one can hear or see them, and no wildlife can get in the way of them.
When I were your age, all round here were fields...
Read the article carefully, or go through some of the comments below. Anyway, it is in water, 5400 km/hr, 1500 m/s. In air, at sea level, it's ~320 m/s, ~1200 ks. bhaloo
I want to die like my grandfather. Peacefully, in my sleep. Not screaming and terrified, like his passengers.
This one is about the US naval policy in the post Soviet era. It mentions anti-mine supercavitation weapons, about one-third of the way down, under "Complementary Systems" http://www.nas.edu/cpsma/nsb/uw2.htm Bhaloo
I want to die like my grandfather. Peacefully, in my sleep. Not screaming and terrified, like his passengers.
In air, at sea level, it's around 320 m/s. The speed they mention (5400 km/hr. ~1.5 km/s) is the figure in water-that's already more than twice as fast as Concorde. bhaloo, the big, dumb bear.
I want to die like my grandfather. Peacefully, in my sleep. Not screaming and terrified, like his passengers.
According to the article, with supercavitation the power is only linear in speed - so the calculations must be somewhat different.
The 'annoy the dolphins till they go away' approach for not hitting them won't have a chance, if the vehicle is travelling faster than sound. I for one thinks the problem with obstacles will be a tough one.
Two things:
1. For navigation/obstacle avoidance underwater, radar is useless, since radio waves just don't propagate far enough. Which leaves sonar. But if you're travelling faster than sound, you'll overtake obstacles before the sonar does. So what else is there?
2. Assuming supersonic travel underwater produces the same kind of shock waves ("sonic booms") that air travel does, damage to the hearing of marine mammals could be extensive. There is already evidence that military sonar causes such damage. This could be much worse.
You realize that sound travels faster underwater than it does in the air. So which speed of sound is it?
You should never take life too seriously - You'll never get out of it alive.
I can't believe I wasted all that mental horsepower arguing with a crank the other day...you're pretty good at pulling meaningless equations out of your ass, huh?
OK., here's the laymans' explanation, broken down into small words so you can understand it. You are not "pushing aside" water. You are moving inside a layer of water that is moving inside another layer of water, etc, etc. The principal behind this method of reducing drag in a fluid environment is called "laminar flow". Do a little basic research before tossing out the equations, huh?
SoupIsGood Food
It's not that simple. You get most
of that energy back. The stuff closing
in behind you can push you forwards,
(and it's not that simple either).
You could use a similar calculation and
prove that tuna couldn't swim that
fast without an onboard nuclear reactor.
But they do, and you don't need a geiger
counter in a sushi restaurant.
http://rareformnewmedia.com/
What you are 'thinking' of is the spermaceti organ of the sperm whale - it is not thought that this has anything to do with hearing but it might be an acoustic lens used in the emitting half of the sonar system, or a buoyancy regulator.
BTW, TinMan00, if you are going to correct someone, especially in the rather graceless way you did rgmoore, it is advisable to check facts first.
Nick
-- "It's a sad day for American capitalism when a man can't fly a midget on a kite over Central Park" - Jim Moran
If density is what matters, then the speed of sound through trolls should be much faster still..
Cheers,
Ben
My usual seat in the cluetrain is at A HREF="http://pub4.ezboard.com/biwethey.ht
The should just mount a giantic spear on the front of it as they go. Free fish and blubber for everyone at the end of every trip!
--
In other words same problems as with modern aviation (most modern planes are incapable of flying with all of their engines shut). So the solution is well known - do not stop.
Baker's Law: Misery no longer loves company. Nowadays it insists on it
http://www.sigsegv.cx/
No, you dumb ass. Sound travels faster through water. Sound travels as a compression wave, a compression wave can travel faster through a denser substance. Sound travels very rapidly through a solid piece of steel.
Take a physics class.
LK
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
hmm well it would have to be a higher frequency than the speed you were travelling, and hopefully it won't work nearly as poorly, since I've seen deer "trapped" in between the effective range of those stupid whistles
(for those of you who have no idea of deer whistles are.. my apologies)
-- Life: Hate the Game... Love the cereal
mulletsgalore.com
hairstyle of the gods!
Now this water has to be pushed at around 340 m/s too
The water doesn't have to be pushed at the same speed as the vessel. If the submarine were completely flat and sufficiently large in the front, then yes, it would need to push the water in front of it like a bulldozer, requiring an unfeasible amount of power. But water flows around a submarine or torpedo -- not in front of it -- and one that is designed with a minimum of drag (for this very reason) should leave the water it moves through relatively still.
Cheers,
IT
Power corrupts. PowerPoint corrupts absolutely.
The US has neutron bombs. Russia has neutron bombs. China has neutron bombs, having stolen the plans from the US. Pakistan has neutron bombs if it wants them. India probably has neutron bombs. The information is out there, and eager nations with a rudimentary level of manufacturing infrastructure and raw materials can build what they want.
Weapons aren't inherently "defensive" or "offensive". They only kill or maim people. "Offensive" and "defensive" are just a measure of political justification and the history behind intentions to kill or maim people.
"If one is really a superior person, the fact is likely to leak out without too much assistance" -- John Andrew Holmes
Nitrous oxide is a greenhouse gas. Don't think environmentalists don't know it.
"If one is really a superior person, the fact is likely to leak out without too much assistance" -- John Andrew Holmes
Well, I got me an AE degree too; such vehicles exist already --they are called wave-riders, riding the shockwave their blunt body is creating. Look at a buncha X Planes, and most significantly the X-33.
Also, all modern ICBM designs induce shock waves at their nose to push air aside and reduce overheating of the rocket body --at some point in the Cold War that was such a huge breakthrough that the US had fake, wooden, sharp noses attached over the blunt noses when moving the ICBMs around...
engineers never lie; we just approximate the truth.
Hear, hear, you're right on the money... this thing is totally unfeasible commercially at least. Plus, to add to your comments: I doubt they can get SONAR to work at all, at least from a supersonic version. It being faster than sound coming from the SONAR and all :-)...
engineers never lie; we just approximate the truth.
I'm feeling even lazier than usual, so I'll be brief:
Underwater rail guns?
MSK
The shuttle's solid rocket boosters basically use thermite: aluminum mixed with ammonium perchlorate if I remember correctly, with a poylmer stabilizer to control the burn rate. The result is aluminum oxide plus other stuff. Aluminum is a toxic chemical if it gets into your system.
www.eFax.com are spammers
nope, go read the article and no biscuit for you. They are actually referring to submarine vehicles exceeding the speed of sound _in water_ (speeds they refer to include 1.5 km/s and 2.5 km/s). Now that's fast. Of course, this is all very theoretical anyway.
The principal behind this method of reducing drag in a fluid environment is called "laminar flow".
.01 P = 3,4 x 10^9. IIRC laminar flow ends around 1000, the this flow is turbulent. An object moving at that speed in air will cause a lot of turbulence. Also, the ration between the density and viscosity is higher in water that air, thus at equal speed the Reynods in water will be higher.
.5 * K * rho * v^2 and you will end up with the exact same result for the power (with K=1).
I know what laminar flow is. However, The flow from such a submarine would be turbulent, not laminar. Let's look at Reynolds number:
R = L*V*rho/mu = 10 m * 300 m/s * 1000 kg/m3 /
As for the "pushing water aside" analogy, you can take Bernouilli's equation with F =
Now, instead of calling names, I'd be very interrested in having a *technical* discussion with you.
Opus: the Swiss army knife of audio codec
2.5 GW is probably achievable with a rocket propulsion over a very short period of time, such as the one required for a torpedo (in ten seconds it can to 3 km). However, this is different for a submarine, which needs to be able to cruise at that speed. The submarine will have at least 100 times the drag and will need to keep that speed for at least several minutes, if not hours to be useful. In terms of total energy, there's about a factor of 1000 between the torpedo and the submarine.
Opus: the Swiss army knife of audio codec
Well, if you consider the problem of bringing a load of 50 tons to 500 km of altitude (ie into orbit) in only one second, you get:
P = 9.8 m/s2 * 50,000 kg * 500,000 m / 1 s = 250 GW.
This means that the rockets of the submarine would be enough to bring the said submarine into orbit in only 1 second! I doubt such a rocket exists.
Opus: the Swiss army knife of audio codec
While a agree that water doesn't have to be pushed at 340 m/s (I'm only roughly approximating), it still has to be pushed aside quite fast in order to produce supercavitation. Remember that the nose is flat, which is not the most hydrodynamic shape. Even if you consider a drag coefficient of .2 (it's probably above that), you get 50 GW power to drive the sub.
Opus: the Swiss army knife of audio codec
Can you explain the objections to the Concorde? I'm not familiar with them. How does it degrade the ozone layer? Or is this just a function of its burning fuel?
If this thing can only go in a straight line, wouldn't the earth's curvature result in this thing shooting out of the ocean and becoming an uncontrollable ICBM?
Creating a vaccuum, and flying around at mach 1.x. Yay. We can kill dolphins with ease. Either bludgeon them or suck them into your supersonic wake for a few hundred miles. Thank you, Russia!
Pax Digitalia
As a couple of people pointed out, sound travels faster in water, and as a general rule, faster in denser material.
To make sense of it, remember that sound is a vibration. Now, if you hit a brick, how fast is the hit transmitted? Likewise, if you hit the air, how fast is the hit transmitted? Finally, if you hit a vacuum, no hit is transmitted, making the speed of sound in a vacuum infinitely slow.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
Unfortunately, this isn't a joke. Scientists are already starting to see some quite nasty effects of very loud underwater sounds on whales and dolphins. There was, for instance, a recent mass beaching incident in which loud sounds deafening the whales was implicated; they were showing classic signs like ruptured eardrums. This is particularly nasty because whales and dolphins depend so heavily on sound for navigation.
There's no point in questioning authority if you aren't going to listen to the answers.
It seems like at very high speeds it might be difficult to navigate around obstacles under water. They might just happen to crash into say a whale, debris, seaweed, etc...
Sounds like a cool technology though.
Well, when the military wants a weapon, i don't think they give too much thought to the environment.
Just look at nukes!
This will give dolphins a HELL of a headache...
1st post!
" ... Ladies and gentleman. In the event we lose cabin pressure, 75 pound SCUBA tanks will drop from the ceiling above you. Place the mask securely on your face, slip into your wet suit, and pull the straps to tighten. Your seat cushion may also be used as a floatation device..."
-- "Computer Literacy? You mean my computer is supposed to read?"
The face of a child can say it all, especially the mouth part of the face.
Speed of sound in air ~340 m/s Speed of sound in water ~1500 m/s Speed of sound in Steel ~5900 m/s So if you were travelling at 2500 m/s then even without the cavitation that will prevent usefulness of SONAR you'd still be blind - you'd get to your target before it's imaged. Of course if you start pinging earlier and use prior pulses, add predicitive software, or rely on your target not moving much between launch and impact it's feasible. It's useful for torpedoes, useless for manned travel.
Is it just me, or every major technological and scientific development during the last 60 years is related to military research? Nuclear power, electronics, Internet, and now, supersonic underwater traveling
Switching to the subject, there is a very serious problem: the supersonic submarine (SSS) will be totally blind. The only scanner type that works underwater, the sonar, uses sound waves, so it is as fast as sound. The vehicle is supersonic, so it will bypass its own signals. Even if it knew what it was running into, there would have been no way of steering it away to safety
Looking at the positive [development] aspects, they could build in-water tunnels (like a pipe that goes INSIDE the ocean). This pipe would not let whales in, and that would also solve the guidance problem.
I looked at the article but didn't see an acutal 'speed' listed. Since soundtravels faster in water is it breaking the speed of sound relative to water?
(1) Hello, it's blind. How the heck is it going to see where it's going? Navy ships' passive sonar capability is seriously reduced at speed because of the noise being produced by the ship going through the water (and the increased noise of the ship's machinery). Active sonar? Well, that *might* help a little, but echo from active sonar has to be heard too (see above).
:o)
obviously, you'd put the eyes in orbit.
(2) Most of the marine life (including seaweed, etc) stays relatively close to the surface. Great, you say -- make the thing travel deeper to avoid skewering whales, etc. Well, that'd be nice, but it's a *lot* harder to cavitate at depth due to the increased pressure (and reduced temperature) -- and the relationship is not a proportional one. Besides being harder to cavitate in the first place, it'd be harder to maintain the bubble around the vehicle (because sea pressure would be trying to collapse it).
a compromise depth of around 40m should do the trick.
(3) Even if you could see where you were going, how would you turn? Control surfaces on the vessel wouldn't do anything because they're in a bubble. Change the direction of the rocket? Kill the bubble.
I imagine there will be traditional, subsonic propulsion systems for the harbor, otherwise, it is a straight shot across an ocean.
(4) Rockets aren't exactly green machines either. Pump our oceans full of chemicals? I don't think so.
The rockets work on powdered aluminum. so there will be an increase of aluminum oxide in the oceans, which isn't going to be much consiedring the VOLUME of the ocean. Besides, there's the potential of magnetic, nuclear and even engines external to the cava-bubble(tm)
(5) The speed required to maintain a cava-bubble (tm) around a large commercial vessel would be MUCH greater than that required to create/maintain a bubble around a small object like a bullet or a torpedo.
and so the engines would have to unleash more force? I don't see the problem here..
(6) Revisiting the "can't see" issue a bit -- assuming they *could* get active sonar to work from within a noisy bubble, what kind of range/warning is it going to give at those speeds? Ever drive really fast at night? Headlights don't give you a whole lot of reaction time, do they? This situation would be much worse.
Revisiting the "eyes in orbit" solution, You'd also have marked lanes under water, and numerous turn-off/breaking lanes to divert the vehicle from collisions. Or, you might have a few accidents per decade, as there isn't much activity at >30m beneath the surface.
(7) This is currently being used for non-manned things that we don't care about. They either run into something or blow up or whatever. Great. Ever wonder what the stopping experience is going to be like for humans? Think about it -- the speed creates the "bubble" which eliminates the drag. Okay, we reach our destination, start to slow down -- bubble collapses -- but guess what, we're still going pretty fast -- now we have a ton of drag slammed onto us. And people whine about a airliner slowing down after a landing.
retractible drag surface fins and maybe 'artificial cavitation' obtained by millions of small bubbles released out of the skin through tens of thousands of small pores designed to reduce drag during transition between speeds.
(8) Cost? Well, I dare say it'd be a heck of a lot more costly than the Concorde.
cost is defined by demand. also, the concorde is too noisy in the air, while this would be more or less quiet.
(9) If people are interested in travelling on submarines, why don't we have commercial submarines now?
There is NO current, practical use for a traditional submarine in commercial travel applications. however, 1 hour to Calais from New York is a monumental increase in travel speeds. I know what I'd choose. have you ever spent 12+hours trying to get to London from the US? I have. The choice is obvious, and that makes it all the much more desirable.
It sure is easy to tear stuff down, isn't it? Next time, maybe you could use that awesome imagination to try and *solve* some problems, instead of just pointing them out.
This pessimism doesn't exactly make you wise, just clever...
:)Fudboy
:)Fudboy
I guess I'm only a Fudboy, looking for that real Transmeta
Since the principle is to vaporize the water in order to create the bubble... instead of doing it by accelerating the projectile to a super high speed in order to create a low pressure zone, and thereby encourage the water to vaporize, what if you heated the nose of the projectile to vaporize the water? Would this reduce the initial speed needed to create the bubble?
Just a thought.
The technology mentioned in the article was developed for the "Shkval" rocket torpedo (image), which was originally (according to intelligence analysis at the time) intended as a "revenge" weapon: the Russian boat in question would fire it back down the bearing a Western (or PLA-N I guess) submarine had already fired upon the Russian boat from. Since it travelled at around 200 knots (which is absolutely insane for even a torpedo) and was armed with a nuclear warhead, it probably had a fair chance of producing the desired datum even without a guidance system.
More recently (spring of 98 or so), the Russians tested a conventionally-armed version, which they could get away with by adding a guidance system to the weapon. Given that the Russian sub fleet barely puts to sea anymore, I have no idea if this is actually in service or not.
:wq
How do you plan to track targets such as whales or icebergs from orbit? Do you plan to catch and mark everything that swims so that you can avoid it? Remeber the higher your speed the smaller the thing has to be to put you into a world of hurt. Even if you mark lanes, you still have the problem that some aminals are going to change depth on you regardless of what you do. You also have the problem of fishermen who will go where ever the fsck they want and fish whatever the fsck they want, and damn your super sonic craft.
as there isn't much activity at >30m beneath the surface.
Plankton are the microscopic animals that for the base of the oceanic food chain. I don't think they will survive the shockwave the craft will produce. Some marine biologist correct me here. Which brings to mind the question of what effect the shockwave will have on the hulls of existing (and especially aging) ships?
cost is defined by demand. also, the concorde is too noisy in the air, while this would be more or less quiet.
What is more annoying the sound of the concord or the sound a thousand environmentalists? More to the point what will the craft sound like underwater. Someone has already raised the point of deafening sonar.
There is NO current, practical use for a traditional submarine in commercial travel applications. however, 1 hour to Calais from New York is a monumental increase in travel speeds. I know what I'd choose. have you ever spent 12+hours trying to get to London from the US? I have.
After all the waiting for sea lanes to clear, the travel into warmer waters to avoid other obsticles, and the constant battle with environmentalists who will inist you are killing everything in the water (wait until you see that first picture of a dead dolphin, its what did in the drag-net fisherment), it will still be cheaper and faster to fly. Besides, a goose will get sucked into a jet engine and appear on the menu for the next flight, a whale will get all the passengers killed.
--locust
It will be extremely difficult to have an operational sonar with a superfast platform. Anybody read Tom Clancy? Remember how he mentions that subs go acoustically blind if they go too fast. Here's a simple underwater (not air) acoustic lesson. A decibel (dB) is defined as 20 log10( P/Po ) with respect to a microPascal (uPa) at 1 m distance. There are additional rules that apply for the frequency content (1 Hz bandwidth) and signal duration (1 sec), but I'll neglect this for simplicity. P is the pressure of the signal, and Po is the reference pressure (1 uPa). 10^5 uPa = 1 dyne/(cm^2) = 10^-6 atmosphere. Hence 1 atmosphere = 10^11 uPa = 20*11 dB = 220 dB.
Now consider geometrical spreading loss. For distances under 10 km, we have spherical loss = 20 log10(D/1m), where D is distance in meters. So for 10m there is a 20dB loss, for 100m there is a 40dB loss, for 1km a 60dB loss.
Put it all together. A good active sonar will put out a 235dB signal. If it travels 50 m out and 50 m back, and if the target is a perfect reflector, and if there is no absorption loss, then the received signal is 195dB=10^-1.25 atmospheres. I would guess that the pressure fluctuations by a superfast system will easily exceed this value. And note, I have chosen to use very conservative numbers.
There is no hard scientific evidence that Navy sonars harm mysticetes (baleen whales), odontocetes (dolphins), or pinnapeds (seals). In terms of physical damage to their hearing mechanisms, the animal would have to be very close. Suppose 1 atm fluctuations are deadly (this is a very conservative value), then the animal would have to be less than 10 m away from a 235dB source. Now if we are talking about long-term hearing loss, then we also need to consider other, more continuous noise sources in the water; namely shipping noise.
Final notes: the dB reference pressure is different for underwater versus air. The dB's I talk about are peak-to-peak dB's. You need to factor in frequency bandwidth and time duration if you want to convert to watts.
How quickly does the object slow down once the bubble collapses? Say you fire a .270 or a 30-06 rifle into water, it nearly stops after going in 1 meter. Either of these 2 rounds fire between 2200 and 3200 feet/second, depending on how much/type of powder, and the weight of the bullet. So, at a minimum, the bullet goes from 2200 fps to 0 in a split second because there's no bubble around it. When the bubble collapses on your manned vehicle, will it slow down just as fast? If so, the people inside are going to be goopy mess of blood, flesh and bones stuck in the nose of the vehicle. So they're going to have to fire the vehicle from some sort of large gun into the water to get the bubble to form, and then at the end of the trip, the bubble will collapse and the vehicle will go from over the speed of sound to relatively nothing in under a second. The chances of this actually working are nearly zero, why don't they just shoot travelers in the head before they get on the thing. What happens if they hit a whale or a stray mine left over from wwII? The thing will mostly be unsteerable, and any change in direction will take several tens of miles or the bubble will collapse. I admit, it's a cool concept, but I'll let them make a few mistakes before I ever get on one.
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Nit to pick: I doubt they're considering 340m/s as Mach 1. Underwater, that's probably gonna be closer to 1.5 Km/s --speed of sound changing with medium density and all that...
engineers never lie; we just approximate the truth.
(4) Rockets aren't exactly green machines either. Pump our oceans full of chemicals? I don't think so.
Big rockets are usually powered by liquid hydrogen and oxygen. The end result is water. Smaller ones may use RP1 (kerosene) and liquid oxyden but the end result of this is still water, plus carbon dioxide. None of these are toxic. Solid fuel boosters usually use some sort of nitrogen compound and the end result is some sort of nitogen oxide, which is also non-toxic (mostly that is, some particular compounds of N and O are called laughing gas IIRC and they make you errr, happy when you inhale).
In general most chemical rocket boosters are quite environmentally friendly.
This article would seem to suggest that:
1) This tech. will allow us to go faster than the Concord.
2) That this would be a viable intercontinental transport system.
It would seem to me that there are many forms of (air) transport faster than the Concord (SR-71 Blackbird, rocket powered vehicals.) However we don't use these for transportation. I seriously doubt that a rocket powered craft is going to cost less to fuel than even the SR-71, much less the Concord.
Considering the small number of people that can even afford to fly the Concord, I doubt that this plan will have much viability outside the military.
your just Pessimists. if we'd of listined to you we'd have never faked landing on the moon!
seems a supersonic airplane would just shatter a few windows... but a supersonic sub would send shockwaves that would kill a hell of a lot of fish... anybody looked into that?
Water is a very efficient transmitter of soundwaves. Adams heard no outboard motors, no dolphins- nothing but a continuous, ceaseless, raging white noise so intense no information could be heard from it at all. All those outboard motors echoed and echoed until the river was one unbearable shriek of sound...
Now. How much louder than a cheap outboard motor is a rocketpowered submarine creating a cavitation bubble so great that a _ship_ fits inside it?
This might work as a military weapon where you don't give much of a damn what else you hit, but use as sea transportation will, surprisingly quickly, leave _no_ form of sonar available for anybody. Not whales, not fish, not oil tankers. I'm not sure how many of these subs it would take but you have to understand how incredibly 'live' water is- sound does not propagate like it does in air. The ambient noise level will simply rise and rise until you can't use sonar for anything anymore- by which time of course, huge amounts of the sea's ecosystem will be hosed, which could also be considered a Bad Thing. That _is_ where the earth gets most of its oxygen y'know ;P
Combining the two results gives us 250 GW of power required to move our submarine.
Wow, and it only takes 1.28 GW to travel through time! That is, if you can find an engine powerful enough to accelerate you to 88 mph. Doc, look out!
Cheers,
IT
Power corrupts. PowerPoint corrupts absolutely.
Consider a "small" submarine with a radius of 2m, going at a speed of 340 m/s (Mach 1 at sea level). The amount of water this submarine has to push aside is pi*(2m)^2*340m/s = 4300 m3/s
That's 4300 tons of water per seconds. Now this water has to be pushed at around 340 m/s too, which corresponds to a kinetic energy of 58000 kJ/ton of water. Combining the two results gives us 250 GW of power required to move our submarine.
This calculation is very approximate, but it still gives an order of magnitude. Even if I'm 100 times over, it still means thousands of megawatts, the power of a big nuclear plant. This is why I doubt we'll see a supersonic submarine soon.
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Any living organism caught by the shock front from this thing is going to be jelly. A megawatts drive underwater would translate directly into millions or billions of fish dead on each trip, and probably several boats and human lives lost as well for good measure.
Someone's got to be kidding.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
Sheesh, give a little techno-babble to a reporter and he has everyone dreaming about daily bullet trips across the Atlantic. Gimme a break.
:o)
This technology is fairly reasonable for what it's being used for (blind, dumb, fast, small things).
It won't scale to large vehicles, and most reasonable humans have an aversion to travelling in blind, dumb, fast things anyway.
Here's a short list of "strikes against it" that immediately come to mind:
(1) Hello, it's blind. How the heck is it going to see where it's going? Navy ships' passive sonar capability is seriously reduced at speed because of the noise being produced by the ship going through the water (and the increased noise of the ship's machinery). Active sonar? Well, that *might* help a little, but echo from active sonar has to be heard too (see above).
(2) Most of the marine life (including seaweed, etc) stays relatively close to the surface. Great, you say -- make the thing travel deeper to avoid skewering whales, etc. Well, that'd be nice, but it's a *lot* harder to cavitate at depth due to the increased pressure (and reduced temperature) -- and the relationship is not a proportional one. Besides being harder to cavitate in the first place, it'd be harder to maintain the bubble around the vehicle (because sea pressure would be trying to collapse it).
(3) Even if you could see where you were going, how would you turn? Control surfaces on the vessel wouldn't do anything because they're in a bubble. Change the direction of the rocket? Kill the bubble.
(4) Rockets aren't exactly green machines either. Pump our oceans full of chemicals? I don't think so.
(5) The speed required to maintain a cava-bubble (tm) around a large commercial vessel would be MUCH greater than that required to create/maintain a bubble around a small object like a bullet or a torpedo.
(6) Revisiting the "can't see" issue a bit -- assuming they *could* get active sonar to work from within a noisy bubble, what kind of range/warning is it going to give at those speeds? Ever drive really fast at night? Headlights don't give you a whole lot of reaction time, do they? This situation would be much worse.
(7) This is currently being used for non-manned things that we don't care about. They either run into something or blow up or whatever. Great. Ever wonder what the stopping experience is going to be like for humans? Think about it -- the speed creates the "bubble" which eliminates the drag. Okay, we reach our destination, start to slow down -- bubble collapses -- but guess what, we're still going pretty fast -- now we have a ton of drag slammed onto us. And people whine about a airliner slowing down after a landing.
(8) Cost? Well, I dare say it'd be a heck of a lot more costly than the Concorde.
(9) If people are interested in travelling on submarines, why don't we have commercial submarines now?
-- CP (Who, by the way, spent several years on submarines; and spent three years teaching Heat Transfer & Fluid Flow)
Environmentalists have conniptions over sonar discombobulating whales migration patterns and maybe even deafening them. They also accuse the supersonic Concorde of contributing to the degradation of the ozone layer. Now combine the two in the form of supersonic underwater travel and you may as well just paint the target on your back for Greenpeace. Had this emerged before environmentalism took such a hold, maybe it would continue to be used, but attempting to introduce it today just isn't going to fly. And I hate to say it, but just maybe that would be a good thing for once.