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-   -   divergence detected in AMG solver: temperature (http://www.cfd-online.com/Forums/fluent/86796-divergence-detected-amg-solver-temperature.html)

mashinsazi April 2, 2011 04:24

divergence detected in AMG solver: temperature
 
I have encountered a difficulty when I was solving my problem.
my problem contains a circular pressure inlet which expands into the special container then flow takes out in smaller velocity outlets.
In the first iteration,FLUENT announced "divergence detected in AMG solver: temperature".
I dont knew how to get rid of that.

I am using Large Eddy Simulation.

alexis June 20, 2011 18:29

I am also using LES and have encountered this problem. Did you find a solution to it?

p4lm0r3 June 21, 2011 15:10

What this means is that your temperature residuals are going to infinite instead of going down. I have had this problem before. Make sure that you are using a good mesh and check to see if your boundary conditions are accurate. Did you use the mesh/check feature? If this is an antisymmetric 2d LES, make sure there are no node lying below the x-axis.

mashinsazi June 23, 2011 01:56

I did whatever you think to solve the problem,but none of them worked.Finally I used constant density model and it was something near to my answer.
I suggest to meet a turbulence expert to solve your LES model probems.

mashinsazi June 23, 2011 02:02

One of friends who is master in CFD gave me some points:

1) use bigger meshes in corners
2) Solve problems without Energy equation in the first Iterations.

p4lm0r3 June 23, 2011 10:46

Thanks I will try that if I have similar problem again in the future.

grummy April 15, 2014 23:43

error: divergence detected in AMG solver: pressure correction
 
Hi, friends
I have a problem like a title, when I run a fluent. My work is four cylinder circular in equispaced arrangement near wall. I used 3D unsteady with second order implicit, and k-omega sst for viscous model. A discretization for pressure, momentum, turbulent kinetic energy, and specific dissipation rate are second order, and pressure-velocity coupling I used SIMPLE. When I run a fluent can iterate, but until 400 iterate, a program was stop. I hope some one could help me or give me a solution. Thanks, before:confused:

shk12345 April 21, 2014 10:39

Hello all

this energy equation has a;ways given me trouble, and i even dont know how my same works sometimes and other times mayn't.


Here are some remedies you can try.

1) Try hybrid initialization.
2) Dont off the energy equation any time.
3) Try to give a initial guess of pressure if you are initializing it with simple initialization. Else try to patch the zone with say pressure=x.
4) Use operating pressure =0.
5) give a pressure of say x at the inlet BC.

Hope with this you may be able to solve the problem

regards
shk

mashinsazi December 9, 2014 10:18

Quote:

Originally Posted by shk12345 (Post 487320)
Hello all

this energy equation has a;ways given me trouble, and i even dont know how my same works sometimes and other times mayn't.


Here are some remedies you can try.

1) Try hybrid initialization.
2) Dont off the energy equation any time.
3) Try to give a initial guess of pressure if you are initializing it with simple initialization. Else try to patch the zone with say pressure=x.
4) Use operating pressure =0.
5) give a pressure of say x at the inlet BC.

Hope with this you may be able to solve the problem

regards
shk

I'm not sure about your answer. I think it doesn't work.


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