Supersonic Submarines

Supersonic Submarines
Science
Noah Meine
September 2, 2014

Supersonic Submarines

            As I searched through science articles I found one in particular that interested me.  This story from Time discusses the possibility of having future submarines travel at supersonic speeds. Yes, supersonic submarines just came ever closer to reality. In other words, this would result in a submarine that could circumnavigate the globe in half a day or, the Pacific Ocean in 100 minutes.  

The original story published by the South China Morning Post reports that Chinese scientists have taken a big step towards creating the world’s first supersonic submarine. These advancements center around one idea called supercavitation.  In detail, scientists at the Harbin Institute of Technology, in China, have made tremendous advances to an old military technology called supercavitation which was first used by the USSR. “Supercavitation would allow submersibles to travel at high speeds”, the Post says.

            This is where science comes in. As Extremetech explains it is much harder for a larger object to travel in water than in air. Simply put, this is because of the increased drag while traveling in water. This is why modern submarines need an insane amount of energy to move through the water. In turn this limits the speed in which they can travel. As of 2014 most submarines can travel at a maximum speed of 40 knots, or approximately 46 mph. But by using supercavitation which essentially envelopes the vessel in a surrounding pocket of air would get around the drag created by water. Supercavitation enabled the USSR’s Shakval torpedo to reach speeds of 230 m.p.h., a much faster speed than anything used by other nations. Theoretically, a vessel using supercavitation, could reach the speed of sound which under water is equivalent to approximately 3,220  m.p.h. (see Figure 1 for supercavitation diagram).

Figure 1, Regular vessel vs Supercavitating vessel 

(Source: http://www.extremetech.com/extreme/188752-chinas-supersonic-submarine-which-could-go-from-shanghai-to-san-francisco-in-100-minutes-creeps-ever-closer-to-reality)

            So now that we know what supercavitiation is and how it is used the question is why are these advancements being made? Well in theory a craft that uses supercavitation would be much faster than anything being used presently and would serve as a huge advantage to any navy. So, where is the limit to supercavitiation? In theory supercavitation (along with the appropriate amount of energy) could allow for speeds up to the speed of sound — which, in water is 3,320 mph, which would allow you to travel from Shanghai to San Francisco (about 6,000 miles) in two hours. Strategically this is a huge military advantage especially to countries that have nuclear missiles. These countries would then have submarine that could travel around the globe in under a day.

            Li Fengchen, a scientist at the Harbin Institute, says the developments concerning supercavitation aren’t limited to military use. Li also goes on to say that even though, military designs are very relevant, supercavitation could also increase civilian use. Li even goes as far to say that supercavitation could be used to help swimmers. Furthermore Li goes on to say that many problems must be solved before any supersonic submarine travel could happen.

Even though it is hard to say when an innovation like this will actually come into use, there will be undoubted repercussions, good or bad.  And the fact that that one day there could be a submarine that could cross the Pacific Ocean in 100 minutes, or less, is just amazing if put to the right use and scary if used as a tool for warfare. Regardless, a development like this just goes to show how science impacts everyone and how incredible human ingenuity can be.

Sources

http://time.com/3180108/travel-transportation-transport-supercavitation-supersonic-submarine-harbin-institute-of-technology-li-fengchen/

http://www.extremetech.com/extreme/188752-chinas-supersonic-submarine-which-could-go-from-shanghai-to-san-francisco-in-100-minutes-creeps-ever-closer-to-reality