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Can not use very high pressure with sonicFoam and rhoCentralFoam

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Old   September 20, 2016, 08:56
Default Can not use very high pressure with sonicFoam and rhoCentralFoam
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Paritosh Vasava
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I am trying to simulate shock wave propagation using sonicFoam and rhoCentralFoam. The idea is to patch a very high pressure for a small spherical region and let the shock wave propagate through the cubical domain.

The simulation goes on nicely without any errors or divergence issues. So, no other setup issues. The problem is with patching high pressure using setField.

I would like to patch as high as 1e11 Pa, but no matter what I do the value is always limited to 105686784 Pa.

For very few trials I managed to patch the high pressure values but in the very next time-step the highest values is switched to 105686784 Pa.

Is sonicFoam or rhoCentralFoam limiting pressure values some how?

I understand that the equation of state for Ideal gas plays role in updating vector fields inside the PISO loop. But I dont know for sure if that is the cause
for this discrepancy.

I am very confused and dont know what to do about it.

Any hint, suggestion or explanation?
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Old   September 21, 2016, 03:44
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Paritosh Vasava
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If I try to patch pressure of order 10^8 (e.g. 9E+8), everything works fine. But any higher order, it simply does not work.
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Old   September 22, 2016, 02:44
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Paritosh Vasava
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It turns out that its just matter of precision. I mean,
Code:
writePrecision  8;//12;//
timePrecision   8;//12;//
When I lowered the precision from 12 to 8, I could patch higher pressure with setField. The case is running fine.

I would still appreciate some comments from other users.
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Old   September 22, 2016, 02:49
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This is strange, if anything I would have expected a limit in one of the thermophysical models. Using a lower precision should also not cause this as far as I can tell.
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