I saw an article yesterday or day before and kind of blew it off. Wish I hadnt now.

It was about Chinese subs going "supersonic" - faster than the speed of sound - say, 750 mph, underwater.

Super Cavitation and all that physics stuff.

How We Can Get Submarines To Travel At Supersonic Speed

August 28, 2014 · by Fortuna's Corner · in China, CIA, DIA, Germany, Intelligence Community, Iran, national security, Navy, Robots In War, Russia, underwater vehicles, US Military · Leave a comment
How We Can Get Submarines To Travel At Supersonic Speed
http://www.fortunascorner.woerdpress.com
Jordan Golson has an August 27, 2014, article on the website Wired.com, with the title above. Mr. Golson writes that Chinese researchers say they are developing a technology that would allow submarines to travel at more than 750 miles per hour — faster than commercial aircraft fly; and, yes — it’s possible,” he notes. “The technology is called supercavitation; and, it’s been around for decades. The idea,” Mr. Golson notes, “is to increase the speed of the object, like say a submarine, or torpedo, by creating a bubble around it — reducing the drag as it moves through the water. The noise of the vehicle typically is designed to create the bubble, and gas often is used to shape the bubble. The Soviets [apparently] used this trick on the Shkval torpedo in the 1960s and ’70s; it was capable of 230mph — but, for no more than a few miles.”
“Obviously, this concept is proven,” writes Mr. Golson. “But, there are practical problems,” he notes. “The devil is in the details,” said Roger Arndt, a University of Minnesota Professor who works within the university’s terrifically named Cavitation and Bubbly Flowers Research Group.”
“One of the stickiest wickets is steering a submerged craft that has little in the way of control surfaces in water,” Mr. Golson observed. “A traditional submarine is controlled by rudder, much like a conventional boat. Steering a supercavitating vessel requires having control planes pierce the bubble, producing great drag. These planes would also be under tremendous force at speed, and would need to be extraordinarily strong.”
Another challenge: “High speeds (for underwater travel) are required to maintain the bubble, perhaps around 45mph, though it would greatly depend on the size and design of the ship. It’s tricky just to reach the speed where a bubble can be created in the first place. So, even if Chinese researchers, at Harbin Institute of Technology’s Complex Flow and Heat Transfer Lab, have made a breakthrough in supercavitation, the limits of standard underwater propulsion will hold them back — especially if they want to make a real submarine. An underwater rocket capable of giving a supercavitating vessel long-range doesn’t exist yet. Building a small torpedo is one thing, building a submarine capable of crossing the Pacific is quite another,” Mr. Golson contends.
The Chinese researchers recently told The South China Morning Post, that they “have developed a liquid membrane that tackles both issues. Continuously sprayed on…it would reduce drag and help get the vessel up to speed. The membrane could allow various amounts of friction to be applied to different sides of the ship, creating a steering effect.” “By combining liquid-membrane technology with supercavitating, we can significantly reduce the launch challenges and make cruising control easier,” Professor Li Fengchen says.
“Details on the new development are scarce, however,” Mr. Golson writes. “”It’s a quantum leap to making a supersonic submarine,” said Arndt. “What they’re showing doesn’t give an inkling of what technology they’ve got.”
“Whatever the Chinese team does have in pocket,” Mr. Golson concludes, “it’s not the only one working on the idea of underwater supersonic travel. Arndt says Iran and Russia are among the many countries doing research, along with the American crew at the University of Minnesota.” “Everybody is getting in on the act.” “So,” Mr. Golson writes, “it may be a while before you clamber aboard a submarine for a quick trip to Shanghai, but the idea isn’t too far fetched either.”
What Other Countries Are Working On This Technology?
Since the story became public, and attracted a significant amount of interest, Professor Li has attempted to distance himself from the story, a staff writer for the South China Morning Post wrote in the August 28, 2014 edition; but, the paper stands by its original comments; and, has a tape of the conversation. The August 28, 2014 edition also adds that in addition to China: “Russia, the U.S., Germany, and even Iran, have all developed and conducted test flights of supercavitating vessels. The paper notes that the VA-111 Shkval torpedo, developed by the Soviet Union during the Cold War, was the first underwater vessel to employ such technology; and, was capable of reaching speeds in excess of 370km/h.” German media in 2005 reported that researchers there had developed an underwater missile system named Barracuda…which allegedly could travel at speeds between 400 and 800km/h. Meanwhile, the United States started developing this technology some two decades ago; and in 2011, a New Hampshire-based company, Juliet Marine Systems…announced it had developed the world’s first prototype, supercavitation boat that was capable of traveling both above, and below the surface of the sea. Technology used in their prototype stealth boat, codenamed GHOST, allowed the vessel to reduce water friction by a factor of 900; and, travel undetected — underwater, at speeds of up to 96km/h.
“Iran has also claimed to have successfully its first supercavitation torpedo, named Hoot, in 2006,” according to the South China Morning Post.
The paper concludes that, “in theory, supercavitation vessels could be able to reach the speed of sound underwater, or 5,800km/h, according to the California Institute of Technology in 2001.” But, it added, “there are still many technological barriers to overcome before this becomes possible; and, no technology currently existing allows vessels to reach, let alone get close, to this theoretical top speed.”
“While the breakthrough, made by the Chinese scientists may allow them to move a step closer to The Holy Grail, of supersonic underwater travel, there are still many technical problems to solve before they can make it a reality — as the Post pointed out in its report.”
Fascinating. Utterly fascinating. And, will we eventually have underwater stealth drones that will be capable of traveling at this speed? Imagine the potential intelligence collection windfall that might be possible — to rapidly deploy to the targeted area, collect the intelligence clandestinely; and immediately return as if we had never been there in the first place. V/R, RCP