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Old   July 9, 2007, 09:45
Default densit.f-subroutine
  #1
Hanti
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Hello Could someone tell me how to write a densit.f-file for a compressible medium like oil including the bulk modulus. It is mainly dependant on the pressure.

Appreciate your help Thx Hanti
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Old   July 10, 2007, 00:05
Default Re: densit.f-subroutine
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Mike
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Include the speed of sound in DENDP, which is a function of bulk modulus and density ~~ 1300 m/s.

Let me know if this works !!
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Old   July 10, 2007, 03:27
Default Re: densit.f-subroutine
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Richard
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To be precise, DENDP is not the speed of sound, it is d(density)/d(pressure) at constant temperature. The speed of sound is the square root of d(density)/d(pressure) at constant entropy.
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Old   July 10, 2007, 04:08
Default Re: densit.f-subroutine
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Hanti
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If I have initialized my model with 100 bar, do i have to substract the 100 bar from PR? Because the pressure values i get are strange (too high, about 300.000). Or has it something to do that in my model there is no pressure boundary and no in- or outlet???
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Old   July 10, 2007, 05:17
Default Re: densit.f-subroutine
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Richard
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The variable PR is relative to PREF. It's likely that your equation of state is in terms of absolute pressure, in which case you have to be careful to code (PR+PREF) in densit when you want pressure.
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