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divergence calculation

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Old   September 6, 2013, 15:44
Default divergence calculation
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amin u3fi
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hi dears...
I am simulating HCCI engine with AVL FIRE
in many time steps my calculation don't converge and go to next step.
in convergence criteria my max number iteration is 150.
my underrelaxation factor are:
momentum=.6
pressure=0.5
energy=0.9
turb kin=0.4
scalar=0.95
do you have any idea?
thnx...
amin_u50
best regards.
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Old   September 9, 2013, 02:49
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Myunghwan Kim
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Hi,

If you write correctly, the factors seem too big.
The factors is surely case dependent.
But I can say in principal.
- momentum: 0.4~0.6
- pressure: around 0.1
- TKE & TDR: around 0.3 (it is recommended to use the same values in two)
- energy: around 0.8

I hope this can help.
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Old   September 9, 2013, 03:59
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amin u3fi
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Hi kimwh
are you sure this factor use for HCCI simulation?? but i see this factors in the CI simulation in tutorial. I think this values has not problem for HCCI simulation
what is your idea?
thnx...
amin_u50
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Old   September 9, 2013, 04:52
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Myunghwan Kim
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Hi amin,

I cannot say just in general because I don't have detail information.
In general, your values seem too high.. especially, pressure.
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Old   September 9, 2013, 04:59
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amin u3fi
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Hi kimhw
thnx a lot for saying your ideas to me...
you are the best my friends...
I examine this factors..
thnx kimhw

amin_h50
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