Author Topic: How long *would* it take Credomar's air to leave?  (Read 995 times)

happyman

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How long *would* it take Credomar's air to leave?
« on: January 27, 2009, 07:44:18 PM »
It's been ages since I took statistical mechanics.  I vaguely remember solving a problem like this (I think it was a bucket full of water emptying, but they're related), but I don't remember any details.

Does anyone have any ideas?  The total pressure is probably going to decrease exponentially, as will most of the other properties, but I haven't a guess as to order's of magnitude.
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mbarker

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Re: How long *would* it take Credomar's air to leave?
« Reply #1 on: January 28, 2009, 05:48:12 AM »
Try an approximation.

First, that hole is 300 m diameter, right? So pi*(r*r) gives about 0.07 Km squared.

Now, the air is 6 K by 60 K. Call it a chunk of stuff 1,696 Km cubed? So line it all up in a 0.07 Km squared line, and you get about 24,000 Km worth to feed through. Run it at 100 Kph, it'll take 240 hours. Double that to 200 Kph, you've still got 120 hours. Even at 400 Kph, you get 60 hours.

And as the pressure drops, the winds will slow down. And temperature drop. Hum, I wonder if the hole would freeze an ice plug? Although those winds might pull something more solid in before that happens.

All roughly speaking.


Howard Tayler

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Re: How long *would* it take Credomar's air to leave?
« Reply #2 on: January 29, 2009, 04:03:22 PM »
I'm not sure, myself. I roughed it out on paper and figured "they've got at least a day before pressures drop noticably," but I don't have the materials handy to build a proper test.