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Atmospheric Density

  1. Jun 22, 2008 #1
    Hey, does anyone have an equation that roughly models atmospheric density from sea level to about 200 km up?
     
  2. jcsd
  3. Jun 22, 2008 #2
    There's not much of an equation for atmospheric pressure that's simple. If you have a CRC handbook you could look up a few values. You should know, as well, that it's quit variable at higher altitudes, dependent on solar activity.
     
  4. Jun 23, 2008 #3
    Hi ZachWeiner,
    Pressure at a height "h" is given by :
    P=(Patm)*e^(-Mgh/RT) [Patm is the pressure at sea level]
    And D=PM/RT
    But there is an assumption that T is const. this formula will only enable you to calculate the density roughly. So do not use it if you want accurate answers.
     
  5. Jun 24, 2008 #4
    I have no excuse for it, but in response to this question, I actually tried an exponential curve of pressure vs. height, and fit it to two points of data; sea level and 100 Km. It was off by 28% at 50 Km. Very disappointing.

    To get a decent curve fit, P = P0 * exp(ah^3 + bh^2 + h) might do it.
     
  6. Jun 25, 2008 #5
    what do you need to model it for? pretty much any fluid mechanics text will tell you in a table at the back.

    lol.. if u really want to model it, put all the numbers into excel and graph it
     
  7. Jun 30, 2008 #6
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