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Old   February 17, 2012, 12:45
Default Negative pressure
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Pierre Castellani
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Hi,
I am trying to make my simulation working as best as possible and I get a strange result using rhoSimpleFoam! After several simulation the presure become highly negative:
:
Averages of p : inlet0 = -407441
:

I'am using the utility patchAverage of simpleFunctionObjects. The presure is defined at the outlet and made zeroGradient at inlet. The velocity inlet is using flowRate.

Strange no?

Thx
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Old   February 17, 2012, 12:54
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Niklas Nordin
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what is the defined pressure at the outlet?
what are the relaxation factors?
what is the initial velocity?
what is the initial turbulent length scale?
what is the outlet bc for velocity?

just to name a few influential factors.

...and its not uncommon to get un-physical values early in the convergence.
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Old   February 17, 2012, 13:35
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Pierre Castellani
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Thanks for your very quick reply, I am (still!!) trying to simulate a vortex tube, I have attached my set up in 0 directory. I reduce the relaxation factor of p from 0.3 to 0.05! For the turbulent lenght scale, are talking about the one that should be used into the calculation of k and epsilon? If it is the case after several (dozens ;-) ) test I put a simple value for both of them even if I see how to calculated them, sorry for that!
Many thanks,
Pierre.
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Old   February 2, 2015, 11:54
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zahra rashidi
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HI,i am intrested to simulate the vortex tube too,do you do that?
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