Now I have a question when I simulate burning of gas.I use eddy dissipation reaction model,ideal gas ,couple implicit solver.

When i have got a good cold flow solution, I pacth 2000K in combustion zone.After some iterations,I've been getting this AMG solver error : Error: Internal error at line 719 in file 'amgif.c'. divergence detected in AMG solve.

I've tried everything I can imagine!!! Would you give me some advice? Thanks a lot, in advance......

Devy 2001.7.10

The problem is that you solution will not converge. There are several causes for this failure. Like a grid which is not good (skewness, connectivity). The RSM turbulunce model is very sensitive to these things. Maybe you should try another model first.

Hi,

Thank you for your reply.

After I have got a good cold flow solution, I pacth 2000K in combustion zone.After1000 or so iterations,Fluent suddenly can't continue to calculate and it also don't reduce the CFL.

I think it is boundary conditions accounting for this error.I try to define one gas species fraction on boundary as zero diffusive flux,this problem doesn't happen.But the gas species fraction is physically value 1.

Now I still don't know how to solve it.

one think you can do is to change the initial values. giving a nonzero value to the initials may converge your problem. and try to keep your under relaxation parameters low.

edvin