*.relax() in bubbleFoam (piso)?

enoch · February 24, 2012, 16:42

I don't understand what the role of .relax() is in the bubbleFoam.

UEqns.H:

UaEqn.relax()

pEqns.H:
p.relax()

alphaEqn.H
alpha.relax()

Does .relax() mean a relaxation factor? the bubbleFoam solver used in OF1.7 adopts the "PISO" algorithm. This algorithm does not need any relaxation factor for solving U, alpha and p. Please enlighten me with you comments. Thanks.

robbirobocop · February 28, 2012, 03:33

If you use PIMPLE you can use relaxation factors. The PISO algorithm (in my opinion) does not have the possibility of relaxation in bubbleFOAM.

So if nOuterCorrectors is > 1 you use PIMPLE and additionally you can optionally use relaxation.

enoch · February 28, 2012, 11:41

I'm using OF 1.7.1 so the bubbleFoam solver adopts "PISO". Do you mean p.relax()/UaEqn.relax()/alpha.relax() do nothing?

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February 24, 2012, 16:42	*.relax() in bubbleFoam (piso)?	#1
enoch Member Jeong Kim Join Date: Feb 2010 Posts: 42 Rep Power: 16	I don't understand what the role of .relax() is in the bubbleFoam. UEqns.H: UaEqn.relax() pEqns.H: p.relax() alphaEqn.H alpha.relax() Does .relax() mean a relaxation factor? the bubbleFoam solver used in OF1.7 adopts the "PISO" algorithm. This algorithm does not need any relaxation factor for solving U, alpha and p. Please enlighten me with you comments. Thanks.

February 28, 2012, 03:33		#2
robbirobocop Member Rob Join Date: Sep 2011 Posts: 55 Rep Power: 15	If you use PIMPLE you can use relaxation factors. The PISO algorithm (in my opinion) does not have the possibility of relaxation in bubbleFOAM. So if nOuterCorrectors is > 1 you use PIMPLE and additionally you can optionally use relaxation.

February 28, 2012, 11:41		#3
enoch Member Jeong Kim Join Date: Feb 2010 Posts: 42 Rep Power: 16	I'm using OF 1.7.1 so the bubbleFoam solver adopts "PISO". Do you mean p.relax()/UaEqn.relax()/alpha.relax() do nothing?