X- momentum divergence in 2D axisymmetric model

hjan23 · January 29, 2015, 10:53

Hey to all experts out there,
I'm simulating an axisymmetric 2D-model for a rotary kiln. The 3D-model has worked properly, however in order to reduce the calculation effort I want to also build a 2D-model.
I have defined it as an axisymmetric model in fluent and have also built my model on the XY-plane along the x-axis, which is the standard symmetry-axis if I got that right.

Here comes my problem:
Whenever I start the simulation I get the following message after one Iteration:

Error: Divergence detected in AMG solver: x-momentum
Error Object: #f

I have already done some Internet research, but nothing so far could fix my problem.

Thanks to everyone who can contribute to this problem,
hjan

CeesH · January 30, 2015, 10:36

I'm not sure if this may cause a divergence error, but is your symmetry axis exactly on the x-axis? if it is off by just a little bit, axisymmetric calculation will give an error. I'm just not sure at what point.

hjan23 · January 30, 2015, 17:11

Thanks for the reply, first of all.

I checked my mesh and it said my geometry starts exactly at y=0.
I also built another geometry, and had the same problem again, so I guess that was not the problem :/

January 29, 2015, 10:53	X- momentum divergence in 2D axisymmetric model	#1
hjan23 New Member Harold Jankowski Join Date: Jan 2015 Posts: 6 Rep Power: 11	Hey to all experts out there, I'm simulating an axisymmetric 2D-model for a rotary kiln. The 3D-model has worked properly, however in order to reduce the calculation effort I want to also build a 2D-model. I have defined it as an axisymmetric model in fluent and have also built my model on the XY-plane along the x-axis, which is the standard symmetry-axis if I got that right. Here comes my problem: Whenever I start the simulation I get the following message after one Iteration: Error: Divergence detected in AMG solver: x-momentum Error Object: #f I have already done some Internet research, but nothing so far could fix my problem. Thanks to everyone who can contribute to this problem, hjan

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January 30, 2015, 10:36		#2
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	I'm not sure if this may cause a divergence error, but is your symmetry axis exactly on the x-axis? if it is off by just a little bit, axisymmetric calculation will give an error. I'm just not sure at what point.

January 30, 2015, 17:11		#3
hjan23 New Member Harold Jankowski Join Date: Jan 2015 Posts: 6 Rep Power: 11	Thanks for the reply, first of all. I checked my mesh and it said my geometry starts exactly at y=0. I also built another geometry, and had the same problem again, so I guess that was not the problem :/