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-   -   Absolute pressure (http://www.cfd-online.com/Forums/flow-3d/66552-absolute-pressure.html)

meysami July 18, 2009 09:17

Absolute pressure
 
Hello,

Would you please tell me how can define a absolute pressure in fluid?
because, when I simulate a free surface and define a void pressure in top area, a logical hydrostatic pressure does not form. I am modeling bubble formation on a hot rod, also I active cavitation model.

best regard

stefmascio July 20, 2009 10:14

if you are using the gravity, and you set an initial pressure with absolute values, then you'll have in your calculation absolute values of pressures.

meysami July 21, 2009 02:55

Dear Stefano
Thank you very much for your answer.
I set gravity and initial pressure with absolute valie, but the pressure was very variable during solving. would you please tell me where are there any mistakes? I must tell you that I have active bubble phase change mode in this calculation

best regards

stefmascio July 21, 2009 04:13

hello meysami,
it is hard to understand what happens in your simulation. I would need more informations. But you can start to look in the online manual, at the chapter "How do I model", to check if you are modeling the bubble with all the data needed or if something is missing.

meysami July 21, 2009 05:21

Dear Stefano

Thank you very much. For bubble modeling I have checked every thing many times, but unfortunately I have not gotten correct answer and the pressure varies during calculation, I do not understand why pressure is variable, if possible for you I can send my perpin file to you via email. I will very pleasure that you help me for solving this problem. I am waiting your answer

Best regard

stefmascio July 21, 2009 05:37

if you use the bubble model then it is right that the pressure changes: it will change following the equation of state of the gas.


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