Bomb Blast!

I have always seen (on movies) or heard of people being “thrown from the blast” of an explosion, and not getting seriously injured, compared to being blown up of course.

So my question is, if you have three people standing in the blast radius of a bomb at different distances, person 1 being closest, person 2 in the middle, and 3 being the farthest. If you know the force of the blast from the bomb, is it possible to position the people at certain distances, so that person 1 and 3 are annihilated, while person 2 gets thrown from the blast and escapes with only a few injuries?

I hope this makes sense.

-Dan

Explosions do some very odd things. During a mission takeoff we had a plane lose an engine and crash tossing a couple of 1000 lb. bombs out onto the ground. A crew of firefighters from the Engineer company was spraying water on it to prevent an explosion, when it exploded. The guy on the nozzle was only about 30 ft. from the bomb. He suffered busted eardrums and was unconscious for an hour or so but was otherwise uninjured and was still alive as of 5 or 6 years ago. Everyone else on the crew was killed.

As a general rule I doubt it. Here’s a nifty primer on explosive damage:

http://www.fas.org/man/dod-101/navy/docs/es310/warheads/Warheads.htm

Damage is caused by two things:

  1. Fragments (stuff flying at you at high speed)

  2. Pressure wave

Doesn’t sound like you are worried about (1) but I’ll note that the number of fragments you get hit with should drop with the square of the distance from ground zero and the velocity of the fragments will also decrease as you get farther away - so Person 3 will get hit with less stuff than Person 2, and the individual fragments will be less dangerous.

That link shows all kinds of cool calculations for blast overpressure but suffice it to say that it also drops off with distance from ground zero.

So if Person 3 gets killed by the blast wave, Person 2 would have been subject to higher pressure from the explosion and they should also be dead. I don’t see how Person 2 could somehow “ride the blast wave” past Person 3, being pushed along by a high pressure wave but not subject to the lethal effects of it.

This is assuming that the blast wave propagates uniformly, the three victims are all in the same posture with no shelter, etc. If #2 is prone and #1 & #3 are standing then I can see #2 surviving and the other two getting killed.

As David Simmons notes, and as illustrated by his anecdote, explosions do some very odd, unpredictable things. The wavefront can act constructively and destructively with itself to produce some very unexpected effects. I’ve personally observed shaped charges used to cut steel girders that did little damage in the “axial” direction. Someone very experienced in explosive interactions, or via the use of some elaborate, high impulse fluid dynamics modeling code like CFD++ can make educated guesses on what will happen but in the end, there’s a certain amount of “Urgh?” in such calculations.

The scenerio suggested in the OP is certainly possible, but I wouldn’t want to be the guy in Position #2, relying on the intuition of a powder monkey to tell me that I wouldn’t really be hurt by the blast. In the F/X industry, there are people who have the experience to set charges that detonate within tens of feet of people without harm…but you’ll note that the big stars are generally replaced with stand-ins for such scenes. Occasionally–with a surprising infrequency, actually–things get fucked up and someone gets hurt.

Don’t play with explosives, kids. One bad day is enough to lose a few fingers or an eye.

Stranger

No argument and thus my “…in general…” and “…assuming the blast wave propagates uniformly…” stuff. I wasn’t saying that it couldn’t happen at all, just that I don’t think it’s likely that anyone could work the numbers out in advance and predict the situation described in the OP.

If you are taking bets on who is most likely to survive, I’d put my money on #3.