Help on judging imbalance plots

stefan23 · December 3, 2011, 16:43

Hello,

I could use some help on judging the imbalance plot in CFX solver module. Unfortunately I could not find much information about this in the help texts. The P-Mass Imbalance in this plot is jumping randomly from -100 to 100, where as the other imbalances seem to stay at zero. I'm wondering how to inteterpret this and if it has got something to with the other residuals. The boundary is a sphere, set to opening, entrainment, static pressure option.

Thank you very much for your help.

Stefan

ghorrocks · December 4, 2011, 04:38

The imbalances are calculated with a divisor of the total flow through the domain (I think, please correct me if I am wrong). If the domain has no entrances or exits so has no net flow, then small imbalances from the continuity equation cause the result to flip from +lots to -lots. It is meaningless in this case, so ignore it.

stefan23 · December 4, 2011, 07:34

Thank you Glenn, that helps.

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December 4, 2011, 04:38		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,701 Rep Power: 143	The imbalances are calculated with a divisor of the total flow through the domain (I think, please correct me if I am wrong). If the domain has no entrances or exits so has no net flow, then small imbalances from the continuity equation cause the result to flip from +lots to -lots. It is meaningless in this case, so ignore it.

December 4, 2011, 07:34		#3
stefan23 New Member Join Date: Nov 2011 Posts: 4 Rep Power: 14	Thank you Glenn, that helps.