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Pressure Wave from Rapid Balloon Expansion

  1. Aug 28, 2009 #1
    Hello physics forum,

    I'm interested in modeling the pressure wave created due to the rapid inflation of a balloon. Say I'm able to rapidly increase the temperature of the air in a balloon, faster than it can equilibrate its pressure with the outside air. It will expand to satisfy PV = T, and radiate a pressure wave. I'm interested in calculating the frequency power spectra of this pressure wave.

    What is the best way to solve for this? One way I can think of is to solve for the velocity of the balloon membrane as it expands, but I'm not sure how I would calculate the membrane velocity. I also thought that I might just be able to use the pressure wave Green's function, and integrate that over the volume of increased pressure.

    Please help! Thanks =)
  2. jcsd
  3. Aug 28, 2009 #2
    Upon further reflection, this bears resemblance to a shock wave. With this context in mind, is there some simple solution?

    I work primarily with optics, I feel like a fish out of water! References, anything would be much appreciated =)
  4. Aug 28, 2009 #3
    Read about Fermi's measurement of the Trinity Site blast in
    http://www.cfo.doe.gov/me70/manhattan/trinity.htm [Broken]
    "Probably the most mundane response of all was Fermi's: he had calculated ahead of time how far the blast wave might displace small pieces of paper released into it. About 40 seconds after the explosion, Fermi stood, sprinkled his pre-prepared slips of paper into the atomic wind, and estimated from their deflection that the test had released energy equivalent to 10,000 tons of TNT. "
    fermi was about 10,000 meters away.
    Last edited by a moderator: May 4, 2017
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