INSCITIA:
Can you break the sound barrier underwater? Has it been done? What speed would you need to do so? And what would happen if you did it?
COGITATIO:
I think it is possible, but would require an incredibly fast speed. My ancient and rusted-out physics acumen reminds me altitude and air density are directly (or is it inversely?!) proportional to the sound barrier. (Something like 967 mph at sea level?) The higher you go, the thinner the air becomes, and the lower the sound barrier becomes. This is, I think, partially why planes make sonic booms at such high altitudes.
Despite my supersonic optimism, a major snag in the possibility of a subaquatic sonic boom, as far as I can see now, is the physical limits water resistance would put on a potentially supersonic subaquatic vessel (PSSV). It may be possible, for engineers to develop and pilots to handle a PSSV on the drawing board and in simulations, but I have a feeling the relatively enormous density of water, coupled with its friction and inertia, would top out any PSSV's velocity below the sound barrier.
A mere James Bond pipe dream?
RESPONSUM:
3 comments:
Sound travels about 1500 m/s in salt water, and slightly faster in fresh water. You've got no chance of breaking the sound barrier underwater, even with today's technology.
c
correction, slightly slower in fresh water.
c
I think that if you made some sort of craft/apparatus that was "sharp" and dense enough (a diamond javelin with a diameter measured in microns, perhaps?) you could do it. The main problem is that the water is so dense that you would have very little chance of overcoming the tremendous friction of the water. And on top of that the speed of sound is so much faster, so you'd have to travel at a tremendous rate.
On the show "Myth Busters" on the Discovery Channel, the guys fired various guns into a pool in an attempt to determine if you could avoid being hit by bullets by diving into a lake or some other body of water. Even the most powerful weapons could not accelerate a bullet fast enough to be anything close to lethal over distances of more than 15 feet or so. The bullets were, in just about every case, torn aport by the friction of the water in less than 6 feet. So, I'd say it's theoretically possible, but practically impossible to do what you propose.
-Matt
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