Species Under-Relaxation Factors

March 24, 2007, 13:29

Hello,

I am currently simulating a laminar flame with a gri2.11 mechanism in fluent. I've got some convergence problems: The residuals of the fuel CH4 won't go below 0.001 and they are oscilating alot. Do you think it's wise to use under-relaxation factors for the species equations? Which under-relaxation factors would you suggest?

It would be really nice, if you could help me.

Greetings, Johannes.

March 24, 2007, 18:54

I would experiment with 0.2 to 0.5 for the under relaxation factors. Are you using first order discretization? Maybe higher order would help or not.

March 24, 2007, 13:29	Species Under-Relaxation Factors	#1
Johannes Guest Posts: n/a	Hello, I am currently simulating a laminar flame with a gri2.11 mechanism in fluent. I've got some convergence problems: The residuals of the fuel CH4 won't go below 0.001 and they are oscilating alot. Do you think it's wise to use under-relaxation factors for the species equations? Which under-relaxation factors would you suggest? It would be really nice, if you could help me. Greetings, Johannes.

March 24, 2007, 18:54	Re: Species Under-Relaxation Factors	#2
A A S Guest Posts: n/a	I would experiment with 0.2 to 0.5 for the under relaxation factors. Are you using first order discretization? Maybe higher order would help or not.

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