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pcaste12 February 17, 2012 11:45

Negative pressure
 
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

niklas February 17, 2012 11:54

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.

pcaste12 February 17, 2012 12:35

1 Attachment(s)
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.

zahrarashidi February 2, 2015 10:54

HI,i am intrested to simulate the vortex tube too,do you do that?


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