divergence calculation

amin_u50 · September 6, 2013, 15:44

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.

kimmhw · September 9, 2013, 02:49

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.

amin_u50 · September 9, 2013, 03:59

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

kimmhw · September 9, 2013, 04:52

Hi amin,

I cannot say just in general because I don't have detail information.
In general, your values seem too high.. especially, pressure.

amin_u50 · September 9, 2013, 04:59

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

September 6, 2013, 15:44	divergence calculation	#1
amin_u50 Senior Member amin u3fi Join Date: Feb 2013 Posts: 137 Rep Power: 13	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.

September 9, 2013, 02:49		#2
kimmhw New Member Myunghwan Kim Join Date: Jul 2012 Posts: 29 Rep Power: 13	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. Krs_gh likes this.

September 9, 2013, 04:52		#4
kimmhw New Member Myunghwan Kim Join Date: Jul 2012 Posts: 29 Rep Power: 13	Hi amin, I cannot say just in general because I don't have detail information. In general, your values seem too high.. especially, pressure. amin_u50 likes this.

September 9, 2013, 04:59		#5
amin_u50 Senior Member amin u3fi Join Date: Feb 2013 Posts: 137 Rep Power: 13	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 kimmhw likes this.

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September 9, 2013, 03:59		#3
amin_u50 Senior Member amin u3fi Join Date: Feb 2013 Posts: 137 Rep Power: 13	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