Diverging Eulerian Multiphase

siara817 · March 7, 2012, 05:23

I am simulating particles in the air.
The geometry is a room and a candle inside.
When I try steady state, it shows from the beginning floating point.
When I use Unsteady with low relaxation factors, it works to some extent, but whenever I change it to steady state, again it starts to diverge.
Any advice is highly appreciated.
Thanks

abdul099 · March 7, 2012, 17:51

Looks like an Eulerian multiphase simulation, right?
In that case, run it laminar, it's very unstable when running it turbulent.
Another try is to reduce under-relaxation factors to very very very low numbers.
Or even better: Try both at the same time!

I understand that's not satisfying, but unfortunately the Eulerian approach is very unstable under turbulent conditions. There are too much equations affecting each other.

siara817 · March 8, 2012, 01:59

Thanks abdul099, it is so nice of you

Kanarya · January 2, 2014, 12:12

Hi,
Did you get the solution with steady state?
I have the same problem.
can you help me!
thanks in advance
best!
Kanarya

March 7, 2012, 17:51		#2
abdul099 Senior Member Join Date: Oct 2009 Location: Germany Posts: 636 Rep Power: 21	Looks like an Eulerian multiphase simulation, right? In that case, run it laminar, it's very unstable when running it turbulent. Another try is to reduce under-relaxation factors to very very very low numbers. Or even better: Try both at the same time! I understand that's not satisfying, but unfortunately the Eulerian approach is very unstable under turbulent conditions. There are too much equations affecting each other. siara817 likes this.

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March 8, 2012, 01:59		#3
siara817 Senior Member siamak rahimi ardkapan Join Date: Jul 2010 Location: Copenhagen, Denmark Posts: 220 Rep Power: 17	Thanks abdul099, it is so nice of you

January 2, 2014, 12:12		#4
Kanarya Senior Member Join Date: May 2011 Posts: 231 Rep Power: 15	Hi, Did you get the solution with steady state? I have the same problem. can you help me! thanks in advance best! Kanarya