Supersonic Submarines!
JoeMerchant writes:
A new laser-based propulsion technique developed by researchers at the Harbin Engineering University in China could help the People's Liberation Army (PLA) build silent yet superfast submarines in the future.
The technology could also power underwater missiles and torpedoes, a South China Morning Post (SCMP) report said.
The concept of underwater laser propulsion isn't new. Japanese researchers first considered it more than twenty years ago.
Except... Google doesn't seem to know about the Japanese work, there's some mentions of a MHD prototype but nothing about turning seawater to plasma for thrust...
Lasers are used to generate plasma inside water, which is then used to make a detonation wave by plasma expansion. The detonation wave is used to propel a craft or weapon ahead.
[...] A research team led by Ge Yang, a professor at the School of Engineering at Harbin University, has now found a way to improve the efficiency of laser propellers using a coating of optical fibers - also referred to as underwater fiber laser-induced plasma detonation wave propulsion.
Using this approach, the researchers claim to be able to generate 70,000 newtons of thrust using just two megawatts of laser power. The thrust generated is similar to that of a commercial jet engine.
In addition to generating thrust, the laser also vaporizes the seawater close to the vessel, creating bubbles on the submarine's surface and reducing water resistance. This phenomenon, known as supercavitation, could potentially allow submarines to travel at supersonic speeds underwater.
Would that be supersonic airspeed? If so, adjusted for depth pressure? Or, is this faster than the much faster speed of sound in water?
Somehow all this exploding water doesn't seem like a quiet mode of operation, but:
More importantly, since the propulsion system is not mechanized, the submarine will not generate any noise, adding to its stealth.
Frankly, the whole thing seems like a response to a recent Red October in April prank.
[Editor note: See: https://nationalinterest.org/blog/reboot/russias-200-knot-shkval%C2%A0supercavitating%C2%A0torpedo-nightmare-us-navy-209759], Not quite in the same league but still faster than anything the West had at the same time--JR]
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