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Posted: 1/30/2011 2:59:09 PM EDT
Scientists at the University of Illinois in the United States have developed and successfully demonstrated a sonic cloak that could make submarines completely invisible to sonar.

The team of scientists, led by mechanical science and engineering professor Nicholas Fang, announced earlier this month that they have produced and demonstrated an acoustic cloak that makes underwater objects invisible to sonar and other ultrasound waves, finally proving what has long been speculated.

“We are not talking about science fiction. We are talking about controlling sound waves by bending and twisting them in a designer space,” Fang said in a statement. “This is certainly not some trick Harry Potter is playing with.”


http://www.defpro.com/news/details/21318/
Link Posted: 1/30/2011 3:05:16 PM EDT
I can see where that would be helpful.
Link Posted: 1/30/2011 3:09:07 PM EDT
Awesome.

I want a cloaking suit like Predator.

Link Posted: 1/30/2011 3:17:20 PM EDT
[Last Edit: 1/30/2011 3:20:45 PM EDT by SuperJanitor]
......."scientists at the U of I have been studying this phenomenon at the state's capitol, where constituents have been invisible to their legislators for decades".......
Link Posted: 1/30/2011 3:23:59 PM EDT
So we could cloak some very large and very jagged rocks off our coast. The threat of running aground on these might keep foreign subs away....
Link Posted: 1/30/2011 3:27:24 PM EDT
"We will pass through the [Chinese] patrols, past their sonar nets, and lay off their largest city, and listen to their [crappy music]... while we conduct missile drills."
Link Posted: 1/30/2011 3:31:19 PM EDT
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.
Link Posted: 1/30/2011 3:31:37 PM EDT
[Last Edit: 1/30/2011 3:31:44 PM EDT by tyman]
Yeah, so let's tell everyone so they can counter it or come up with it on their own/steal our technology...let's do that!
Link Posted: 1/30/2011 3:33:44 PM EDT
So, when do we sell it to the Chinese?
Link Posted: 1/30/2011 3:38:17 PM EDT
Originally Posted By 4v50:
So, when do we sell it to the Chinese?


They've already made a couple of payments.
Link Posted: 1/30/2011 3:38:58 PM EDT
Today we schail into history
Link Posted: 1/30/2011 3:39:59 PM EDT

Originally Posted By Afterwork_Ninja:
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.

That makes no sense. Active sonar pings out sound and picks up what bounces back, like radar does with electromagnetic radiation.
Link Posted: 1/30/2011 3:42:53 PM EDT
So, this would only work on active sonar right?
Link Posted: 1/30/2011 3:42:58 PM EDT
I've always wondered, does the government ever step in when universities make discoveries like this to make sure things remain classified, or is it purely up to the schools to decide if they want to take any action to keep stuff like this away from spies etc.?
Link Posted: 1/30/2011 3:44:07 PM EDT
Originally Posted By OBird:
I've always wondered, does the government ever step in when universities make discoveries like this to make sure things remain classified, or is it purely up to the schools to decide if they want to take any action to keep stuff like this away from spies etc.?


Where do you suppose the funding comes from?
Link Posted: 1/30/2011 3:47:14 PM EDT
[Last Edit: 1/30/2011 3:52:16 PM EDT by PugglePod9000]
Originally Posted By Afterwork_Ninja:
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.


Sound reflects off ANY change in density.
The sound is traveling through water at about 4850 FPS. When it hits the steel of the hull some of it is reflected (even though steel is a better sound conductor than water) the rest ACCELERATES through the steel...
The best reflections occur when it transitions from a good (sound) conducting medium (the steel hull) and hits the less conductive air inside the ship.

Disclosure: I am a qualified submariner and a sonar technician.

Originally Posted By raven:

Originally Posted By Afterwork_Ninja:
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.

That makes no sense. Active sonar pings out sound and picks up what bounces back, like radar does with electromagnetic radiation.


It isn't intuitive -but it does work that way.

Link Posted: 1/30/2011 3:49:18 PM EDT
[Last Edit: 1/30/2011 3:51:33 PM EDT by LazarusLong]
As I understand it subs don't use active sonar so this wouldn't do any good in regards to sub on sub warfare

It might have application in defeating sub finding sonar buoys though or sonar originating from a ship.
Link Posted: 1/30/2011 3:49:33 PM EDT

Originally Posted By Pita_146:
So, this would only work on active sonar right?

From the article:

The technology could also be applied to other areas of submarine stealth, such as cavitation, whereby small bubbles form and implode around fast moving objects like propeller blades. Fang and his group believe they could harness their cloak’s properties to balance energy in caviation-causing areas. Thus, the cloak could be used to keep noise from getting out of a submarine in addition to stopping sonar waves from bouncing back to their source.
Link Posted: 1/30/2011 3:51:32 PM EDT
[Last Edit: 1/30/2011 3:54:05 PM EDT by PugglePod9000]
Originally Posted By LazarusLong:
As I understand it subs don't use active sonar so in most cases there's nothing to detect


Not true.

Every pump spinning produces vibration, the electrical system hums, hydraulics "woosh", lots and lots of opportunity to detect a contact...

Open ocean -passive sonar is the way to go-

In shallows (and you might be suprised how much time some boats spent there) active is a handy tool.
Link Posted: 1/30/2011 3:53:18 PM EDT
Originally Posted By PugglePod9000:
Originally Posted By LazarusLong:
As I understand it subs don't use active sonar so in most cases there's nothing to detect


Not true.

Open ocean -passive sonar is the way to go-

In shallows (and you might be suprised how much time some boats spent there) active is a handy tool.


Edited orginal post to be more clear, I guess this wouldn't do anything to hide a sub from another sub but it would hide it from a ship?
Link Posted: 1/30/2011 3:53:41 PM EDT
Originally Posted By OBird:
I've always wondered, does the government ever step in when universities make discoveries like this to make sure things remain classified, or is it purely up to the schools to decide if they want to take any action to keep stuff like this away from spies etc.?


Most of it is funded through grants and the run the press releases through .gov. My wife works for a small company that produces the wafers in night vision. They do other work too and that's pretty much how it rolls.
Link Posted: 1/30/2011 3:58:29 PM EDT
Originally Posted By 03Vet:
So we could cloak some very large and very jagged rocks off our coast. The threat of running aground on these might keep foreign subs away....


While it seems obvious that submarines would feel their way around the ocean with sonar pinging away in search of obstacles, and targets - the reality is that they pretty much drive around with the windows blacked-out, and their fingers crossed.

Link Posted: 1/30/2011 3:59:10 PM EDT

Originally Posted By fatalerror113:

Originally Posted By Pita_146:
So, this would only work on active sonar right?

From the article:

The technology could also be applied to other areas of submarine stealth, such as cavitation, whereby small bubbles form and implode around fast moving objects like propeller blades. Fang and his group believe they could harness their cloak’s properties to balance energy in caviation-causing areas. Thus, the cloak could be used to keep noise from getting out of a submarine in addition to stopping sonar waves from bouncing back to their source.

I hardly ever click the link and read the whole article. Way too much effort involved in that.
Link Posted: 1/30/2011 4:00:47 PM EDT

Originally Posted By PugglePod9000:
Originally Posted By LazarusLong:
As I understand it subs don't use active sonar so in most cases there's nothing to detect


Not true.

Every pump spinning produces vibration, the electrical system hums, hydraulics "woosh", lots and lots of opportunity to detect a contact...

Open ocean -passive sonar is the way to go-

In shallows (and you might be suprised how much time some boats spent there) active is a handy tool.

Torpedoes also use active sonar to home in on their targets, correct?
Link Posted: 1/30/2011 4:09:53 PM EDT
Originally Posted By PugglePod9000:
Originally Posted By Afterwork_Ninja:
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.


Sound reflects off ANY change in density.
The sound is traveling through water at about 4850 FPS. When it hits the steel of the hull some of it is reflected (even though steel is a better sound conductor than water) the rest ACCELERATES through the steel...
The best reflections occur when it transitions from a good (sound) conducting medium (the steel hull) and hits the less conductive air inside the ship.

Disclosure: I am a qualified submariner and a sonar technician.

Originally Posted By raven:

Originally Posted By Afterwork_Ninja:
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.

That makes no sense. Active sonar pings out sound and picks up what bounces back, like radar does with electromagnetic radiation.


It isn't intuitive -but it does work that way.



Is the thermocline layer as effective at avoiding detection as they make it out to be in books and movies?

Does it affect the active sonar of torpedoes?
Link Posted: 1/30/2011 4:47:53 PM EDT
[Last Edit: 1/30/2011 4:49:41 PM EDT by Sparkym37]
"When will we be selling it to China?"

Probably setting up a factory now.
Link Posted: 1/30/2011 4:50:35 PM EDT
How long before it's adapted for underwater mines?
Link Posted: 1/30/2011 5:01:23 PM EDT

Originally Posted By tyman:
Yeah, so let's tell everyone so they can counter it or come up with it on their own/steal our technology...let's do that!

Exactly, what happened to loose lips sink ships?
Link Posted: 1/30/2011 5:05:58 PM EDT

Originally Posted By Afterwork_Ninja:
Originally Posted By PugglePod9000:
Originally Posted By Afterwork_Ninja:
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.


Sound reflects off ANY change in density.
The sound is traveling through water at about 4850 FPS. When it hits the steel of the hull some of it is reflected (even though steel is a better sound conductor than water) the rest ACCELERATES through the steel...
The best reflections occur when it transitions from a good (sound) conducting medium (the steel hull) and hits the less conductive air inside the ship.

Disclosure: I am a qualified submariner and a sonar technician.

Originally Posted By raven:

Originally Posted By Afterwork_Ninja:
Speaking of Tom Clancy, I read in one of his books that active sonor doesn't detect the metal hull of the sub. It detects the air inside the ship. I don't know if it is true or not though.

That makes no sense. Active sonar pings out sound and picks up what bounces back, like radar does with electromagnetic radiation.


It isn't intuitive -but it does work that way.



Is the thermocline layer as effective at avoiding detection as they make it out to be in books and movies?

Does it affect the active sonar of torpedoes?

Depends. Sometimes it's strong, sometimes it's completely non-existent. Also depends on where the sub and where the torpedo are in relation to one another––so it can also work to your disadvantage.

Link Posted: 1/30/2011 5:31:07 PM EDT
Originally Posted By SuperJanitor:
Originally Posted By OBird:
I've always wondered, does the government ever step in when universities make discoveries like this to make sure things remain classified, or is it purely up to the schools to decide if they want to take any action to keep stuff like this away from spies etc.?


Where do you suppose the funding comes from?


This. The navy doles out tons of grants to Universities.
Hell, both Penn State Engineering and ARL gets most of its money from DoD and especially Navy, including the project I'm on.
The building the Watertunnel is housed in doesn't allow cell phones or non US citizens inside as its all Navy funded submarine and torpedo research.
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