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Re: shock wave as pressure builds in a vacuum?



At 12:44 AM 5/28/2003 -0400, you wrote:
/snip/
It is experimentally observed that under these conditions
("catastrophic venting"), the membrane is sometimes broken. One
colleague argues for some kind of shock wave, essentially an
overpressure transient at the membrane as the air rushes in. I argue
that there is little or no physics to support that, and that the
membrane failure is due to an excessive deflection rate (dx/dt, as
the pressure increases rapidly) that it cannot withstand from a
mechanical standpoint.

Any thoughts?


Stefan Jeglinski

For what it's worth department: an experimental arrangement
sometimes used to create sonic air flow in a test channel uses
a vacuum chamber on the exhaust side, and atmospheric air
on the inlet.
So one can suppose that a rapid air flow impinges on the
delicate? membrane and perhaps especially if it flutters,
it may breach. I suppose there is some reason for keeping
the membrane thin? Perhaps a strain-gage is attached to it?

Brian Whatcott