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-   -   reactingfoam - pressure field (http://www.cfd-online.com/Forums/openfoam/114759-reactingfoam-pressure-field.html)

yaqb March 17, 2013 09:14

reactingfoam - pressure field
 
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I have just started with OpenFoam, so I am still lost in the dark.
I have a question.Can anyone explain me why the reactingFoam does not calculate the pressure field? I have run the tutorial example and the pressure field is uniform from the beginning until the end of the simulation. What is the reason of that?

The screenshot I have uploaded is from the 0.3 sec.

mturcios777 March 18, 2013 12:26

Please describe your case setup and boundary conditions. Right now you don't have much for us to go on...

yaqb March 18, 2013 14:59

Thank you for you answer
- In fact I have been trying to modify the reactingFoam to make it working with changed geometry and always got the uniform pressure field.
-Than I run the case from tutorial - just went to the tutorial and run the case without changing anything . At the end I also got the uniform pressure - it is shown on the picture I have uploaded.

It just have no sense for me.... why the solver does not compute pressure in this case?

mturcios777 March 19, 2013 11:55

Which tutorial are you running? I ask because that looks like the geometry for cavity, and the geometry for reactingFoam (based on PitzDaily) is very different.

kalle March 20, 2013 02:43

I guess you are running the counterFlowFlame tutorial. Default, the tutorial saves out in ascii with 6 digits precision. This case operates at a pressure of 1e5 Pa, while flow induced pressure differences are about 0.015 Pa. These small differences are completely lost at save-out. Switching to binary in controlDict, and you can see the differeneces. It appears though as if paraview is having trouble displaying the field still.

Hack: switch to ascii and precision 16. Open 0.3/p in a text editor and search replace "100000." with "0." to remove the offset of 100000. Now paraview will show a nice smooth pressure field actually used by the solver.

K

yaqb March 21, 2013 05:54

Solved
 
Yes! You were completely right , the pressure varies less than 1 Pa - right now I can see everything :)

Thanks a lot!


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