Undetectable Submarines

The Next Generation of Silent Submarines Could Defeat Radar and Sonar Sensing

Submarines are revolutionary marine stealth and attack vessels.  These highly efficient vehicles are used by the many navies of the world (or at least the ones that can afford them), and they continue to lurk within the depths of the ocean as we speak.  Maybe you thought, "O man, I didn't think that these things were really that effective in war or anything nowadays".  Well, they are.  

Over the years, engineers and other scientists have succeed in making submarines highly efficient war machines with multiple functions including:  launching ballistic missiles at land targets from underwater, reaching deeper and deeper depths with every dive, advanced on-board communications systems, and silent travel.  Submarines are a menace, they can launch surprise attacks on an unsuspecting enemy and can even retrieve vital Intel without leaving a trace.  So how exactly do they make submarines to be so tricky to detect?  The answer lies in the usage of meta materials and cloaking technology.

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 meta materials—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.

Complete Cloaking and Zero Wake

"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. (See image below).

 

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.

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So yeah, adding the whole "undetectable" factor to the submarine game makes these vehicles 100 times more deadly to foreign military forces.  Like I said above, they can be used in attack, stealth, and patrol missions.  And if you don't want anyone else knowing about what you are doing, then using these new submarines would be perfect.  Currently, the Office of U.S. Naval Research declined to comment on any new cloaking programs, but it is clearly aware that other military forces may be working on them.  In fact, the U.S. Navy began a Meta material Countermeasure and Defeat Program as early as 2009.

As far away as this new groundbreaking stealth technology is from being standard issue on first class submarines around the world, we still need to acknowledge that it's all pretty cool.  Scientists can engineer meta materials 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.  I mean, that's never been done before ever.  This is history in the making.  So far, scientists have cloaked simple shapes such as cones and cylinders, but more complex shapes could be cloaked as well.

Thanks guys!  Check out the link below for the full article:)

http://www.popsci.com/technology/article/2011-12/next-generation-silent-submarines