control number iterations per equation

CeesH · March 2, 2016, 09:27

Hi all,

When I'm running a transient simulation of a gas-liquid flow (with population balance), it seems the population balance equations cannot 'keep up' with the volume fraction equation.

Things tend to get much better if I disable volume fraction eq. for a while (under solution controls), converge the pop. balance variables, enable volume fraction for a few steps again, and so on. But of course, it's not really viable to keep on doing this by hand. Is there anyway to automate this? so say, execute 10 population balance iterations for every volume fraction iteration?

Best,
Cees

LuckyTran · March 2, 2016, 13:05

Can this be done through under relaxation factor instead? It doesn't disable the equation but does slow its changes.

CeesH · March 2, 2016, 13:25

hm, maybe if I go really low. with UR for vol. frac. around 0.1 it doesn't seem to be helping a lot yet, but I'll play with it a bit more

March 2, 2016, 09:27	control number iterations per equation	#1
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	Hi all, When I'm running a transient simulation of a gas-liquid flow (with population balance), it seems the population balance equations cannot 'keep up' with the volume fraction equation. Things tend to get much better if I disable volume fraction eq. for a while (under solution controls), converge the pop. balance variables, enable volume fraction for a few steps again, and so on. But of course, it's not really viable to keep on doing this by hand. Is there anyway to automate this? so say, execute 10 population balance iterations for every volume fraction iteration? Best, Cees

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[OpenFOAM.org] OF2.3.1 + OS13.2 - Trying to use the dummy Pstream library	aylalisa	OpenFOAM Installation	23	June 15, 2015 15:49
SigFpe when running ANY application in parallel	Pj.	OpenFOAM Running, Solving & CFD	3	April 23, 2015 15:53
Compressor Simulation using rhoPimpleDyMFoam	Jetfire	OpenFOAM Running, Solving & CFD	107	December 9, 2014 14:38
Micro Scale Pore, icoFoam	gooya_kabir	OpenFOAM Running, Solving & CFD	2	November 2, 2013 14:58
pisoFoam with k-epsilon turb blows up - Some questions	Heroic	OpenFOAM Running, Solving & CFD	26	December 17, 2012 04:34

March 2, 2016, 13:05		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,751 Rep Power: 66	Can this be done through under relaxation factor instead? It doesn't disable the equation but does slow its changes.

March 2, 2016, 13:25		#3
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	hm, maybe if I go really low. with UR for vol. frac. around 0.1 it doesn't seem to be helping a lot yet, but I'll play with it a bit more