Underwater Explosions

[unipidity]

Hi all,
I have heard that the pressure from an underwater explosion exceed that of an atmospheric explosion by a factor of 25, presumably due to incompressability. How do I calculate this from some basic physics?

 

[Gibsons]

Originally posted by: unipidity
Hi all,
I have heard that the pressure from an underwater explosion exceed that of an atmospheric explosion by a factor of 25, presumably due to incompressability. How do I calculate this from some basic physics?

This pdf might help... if nothing else, it has some references at the end.

 

[capn k]

The "Bible" on the theory of Underwater Explosions is the first reference in the PDF list given above. Cole, R. H., ?Underwater explosions?, Dover Publications, New York (1948). Unfortunately it is out of print, but there are lots of copies around. I have one.

A partial non-nswer to your question is that it depends on where you measure the pressure! The equation of state for the explosive is the same whether it is in water or the atmosphere. How it propagates away from the detonation point is influenced by the medium that it is in. Water, though not 100% incompressible, is a great conductor of the shock wave initiated by the explosion and conducts it very efficiently away from the initiation point. The pressure is obviously very high near the detonation point and falls off rapidly in a 1/R relationship (R being the distance from the charge.

There are several organizations that have developed computer codes using the equation of state of the explosive and the medium that the explosive is detonated in to determine the pressure field around the initiation point.

 

[Howard]

Originally posted by: capn k
The "Bible" on the theory of Underwater Explosions is the first reference in the PDF list given above. Cole, R. H., ?Underwater explosions?, Dover Publications, New York (1948). Unfortunately it is out of print, but there are lots of copies around. I have one.

A partial non-nswer to your question is that it depends on where you measure the pressure! The equation of state for the explosive is the same whether it is in water or the atmosphere. How it propagates away from the detonation point is influenced by the medium that it is in. Water, though not 100% incompressible, is a great conductor of the shock wave initiated by the explosion and conducts it very efficiently away from the initiation point. The pressure is obviously very high near the detonation point and falls off rapidly in a 1/R relationship (R being the distance from the charge.

There are several organizations that have developed computer codes using the equation of state of the explosive and the medium that the explosive is detonated in to determine the pressure field around the initiation point.

Great first post. Welcome to Anandtech!