Defense systems can detect stealth submarines using two methods: sonar, which bounces sound waves off a craft, and radar, which can identify subtle disturbances on or below the ocean's surface that can indicate a sub at depth. Now scientists are developing acoustic and fluid cloaking methods that could defeat both tactics.
The acoustic cloak would use metamaterials—engineered composites designed to display certain natural properties, such as magnetism or refraction—to bend sound waves around the craft, making it undetectable to sonar. A fluid cloak would alter the flow of water over a craft, concealing any wake or turbulence and eliminating the threat from radar. Both kinds of material could, in theory, be fashioned into a sheath that would slip over an existing attack submarine. The Office of Naval Research declined to comment on any new cloaking programs, but it is clearly aware that other militaries may be working on them—the Navy began a Metamaterial Countermeasure and Defeat Program in 2009.
A material that combines acoustic and fluid cloaking systems is possible, says Yaroslav Urzhumov, an assistant research professor at the Center for Metamaterials at Duke University, but won't happen for a while. If and when it does, Urzhumov speculates that the final product would appear as a housing of fine, water-permeable mesh.
A fluid cloak would consist of hundreds of small water jets, similar to those found on Jet Skis, housed within a mesh sheath. The jets would accelerate water as it entered the sheath [red and orange] and slow it as it left [green and blue]. With no net change in speed, the water would close around the sub seamlessly, generating no disturbance.
A sub traveling at depth can still broadcast its location. The bulges on the ocean surface made by an object moving underwater, called the Bernoulli hump [red, in the image above], may be detectable from a craft as deep as 1,000 feet. Like any vessel, subs leave a V-shaped trail [green], known as a Kelvin wake, which can also be detected on the surface. Fluid cloaking would eliminate both the Bernoulli hump and Kelvin wake.
Scientists can engineer metamaterials that bend sound waves around an object by combining materials of different densities. Waves speed up when they hit the cloak and slow on departure, creating no net distortion. So far, scientists have cloaked simple shapes such as cones and cylinders. But, Urzhumov says, more complex shapes could be cloaked as well.
Read more about the invisible warriors of the future: The engineering breakthroughs that will make everything from planes to subs to soldiers...disappear.
I dont understand the whole focus on new "meta-materials". Ben Rich (former head of Skunk Works) claims in his book that current stealth technology is more than capable of countering active sonar. He goes on to say that they built a model submarine hull using the same flat-pannel generation 1 stealth as used in the f-117 and reduced its signature by "several orders of magnitude." As usual it was rejected by the USN.
And this was in the 1980's..............................
Google(tm) for "time reversed" and "retroantenna". There have been a number of papers published over the past five to ten years, and it is IMO not at all unlikely the technology is now in use to cancel active sonar and radar without the user being aware he is being jammed.
I wonder if those nano ears could hear it...
Welcome to the big poker game. The "new" technology that you see made public is already far out-dated. The Military keeps anything relevant or that posses a real threat to it's security classified. So if you see it in publications, do the math, it's no longer relevant to military use.
Playing Devil's Advocate since 1978
"The only constant in the universe is change"
-Heraclitus of Ephesus 535 BC - 475 BC
this would be a new technology, i'm sure we corrently evade or defeat active sonar, this would just be better or not pan out at all, cheers
seeing that submarines constitute the first and last line of defense for the US i would say they are already using this technology....why else would you allow its existence to be released to the public unless you're already using it and its well established
On one hand, if we civilian publications are just now hearing about it, it's already been in the military's hands for quite some time.
On the other, it takes quite a while to develop and build these systems on any real kind of scale past the experimental stage, and no one currently has the technology to easily counter our current-gen stealth tech, much less these new meta-materials. So there's no reason to rush these into production short of WW3. We might see these rolled out by 2020 when our current subs start dying off from old age and the price of manufacturing decreases, but right now our current tech is perfectly acceptable for shadowing Chinese and Iranian subs.
"i would say they are already using this technology....why else would you allow its existence to be released to the public unless you're already using it and its well established"
huh? I dont see any logic in that statement at all!
Aether or boot they already have it isn't the concern and i would only be concerned if another country came up with the idea.
Inlay rob: the other dude was right if the military gave us info.now it probably isn't new. If the give out important information all "spies" would have to do would be:get a passport and pay an American for details on certain projectsm not the smartest person in the world so.anything i say is a guestimate
There are probably active subs that already use this technology. That being said, there are also probably only about 3 that are in working condition beyond the experimental testing phase. By the time ANY new technology can be mass produced, it is usually "out of date." But notice the people that are releasing this information. The military doesn't control every single professor that comes up with concepts useful to our troops. These aren't government officials talking. It's still possible the military doesn't have this tech ready for use at all.