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divergence detected in AMG solver: temperature

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Old   April 2, 2011, 05:24
Default divergence detected in AMG solver: temperature
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kamran
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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.
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Old   June 20, 2011, 19:29
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Alexis
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I am also using LES and have encountered this problem. Did you find a solution to it?
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Old   June 21, 2011, 16:10
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John Palmore
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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.
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Old   June 23, 2011, 02:56
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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.
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Old   June 23, 2011, 03:02
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kamran
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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.
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Old   June 23, 2011, 11:46
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John Palmore
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Thanks I will try that if I have similar problem again in the future.
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Old   April 16, 2014, 00:43
Post error: divergence detected in AMG solver: pressure correction
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grummy
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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
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Old   April 21, 2014, 11:39
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shoeb khan
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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
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Old   December 9, 2014, 10:18
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kamran
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Quote:
Originally Posted by shk12345 View Post
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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