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-   -   Setting 'lowest pressure' pMin in compressibleInterFoam (https://www.cfd-online.com/Forums/openfoam/70686-setting-lowest-pressure-pmin-compressibleinterfoam.html)

 kjetil December 2, 2009 10:49

Setting 'lowest pressure' pMin in compressibleInterFoam

Dear foamers,

the only thing remaining in my university term project, is to get get my water-air simulation from solver interFoam to the compressibleInterFoam. I have searched for info on how to use the compressible solver, but nothing of any use exists. My main problem is that setting the pressure pMin to a fixed value, the internal pressure fluctuates constantly/periodically - and in turn so does the velocity field. Does anybody have any hints at all to what to set pMin to, to get a stable simulation going? And what is the purpose of this pMin in the first place?

Thank you.

 Marta April 21, 2010 13:30

Hi! Do you know how to set the pMin parameter correctly depending on the case you are solving? How does it affect the solution exactly?

Thanks

Marta

 kjetil April 21, 2010 17:00

Hi Marta
unfortunately I didn't get an answer to this - but you might try to set it to zero or something close to zero, as 10E-6 or around that.

So, I too wish that someone could elaborate on the use of this pMin.

 flowman April 21, 2010 20:40

Hi Kjetil,

compressibleInterFoam uses an equation of state: rho=p*psi. For isothermal expansion psi=1/RT. The value of the minimum pressure, pmin, must be set to something greater than zero to ensure the equation of state returns a density greater than zero to the solver.