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Old   September 16, 2010, 09:34
Default Pressure in rhoSimpleFoam
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Vitor Braga
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I'm running a simple simulation, an axial air flow through a pipe. It's compressible, with a Mach = 0,5 . I'm still setting the BC's, the problem is: which pressure I should set in the 0/p file? Is it the relative or absolute pressure?

I know that using fixedValue means that I'm setting static pressure, and totalPressure sets static+dynamic. But do I need to add the atmosferic pressure?

Let's say, if my atm pressure is 101 kPa and I want relative totalPressure @ inlet equal to 18 kPa. Then I should use 18 or 119 kPa in the 0/p file?

Thanks a lot.

Vitor
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Old   September 16, 2010, 10:03
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Stefan Herbert
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Hi Vitor,

of course you have to define 119 kPa in your example. Atmospheric pressure is not defined elsewhere. Therfore the absolute pressure is needed to make sure that the density is calculated correctly.

Regards,
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Old   September 16, 2010, 11:49
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Vitor Braga
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Indeed. I thought maybe the atmosferic pressure would be set in other file.
Thank you for your reply.

And sorry for the fundamental question...
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