HELP!a problem when starting the unsteady iteration in Fluent

usst139 · January 19, 2010, 09:56

I have a problem when starting the unsteady iteration in Fluent,and it said——"warning:non-positive volumes exist.
Error:divergence detected in AMG solver

ressure correction
Error object

)

I guess something wrong with my original grid in Gambit?
hELP ME!THANK YOU!

radix · January 20, 2010, 13:41

You might to reconsider your meshing result from GAMBIT. Check your mesh result. Have a look on your right corner of your GAMBIT window to this. The 'non-positive volume' exist due to the highly-generated skewness.
As for the divergence problem,you can prevent this by setting your 'under-relaxation factor'. Make it smaller.
Hope this short reply would solve your problems.

Regards,
Raditya

usst139 · January 21, 2010, 02:37

Thank you for your kind advice,Raditya

Yes,the blade in my model has a very high skewness,so I 'm trying to use the Boundary Layer or Sizefunction to make a better mesh

January 19, 2010, 09:56	HELP!a problem when starting the unsteady iteration in Fluent	#1
usst139 New Member xuusst Join Date: Jan 2010 Posts: 4 Rep Power: 16	I have a problem when starting the unsteady iteration in Fluent,and it said——"warning:non-positive volumes exist. Error:divergence detected in AMG solver ressure correction Error object) I guess something wrong with my original grid in Gambit? hELP ME!THANK YOU!

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January 20, 2010, 13:41		#2
radix New Member Raditya Wiranegara Join Date: Aug 2009 Location: United Kingdom Posts: 22 Rep Power: 17	You might to reconsider your meshing result from GAMBIT. Check your mesh result. Have a look on your right corner of your GAMBIT window to this. The 'non-positive volume' exist due to the highly-generated skewness. As for the divergence problem,you can prevent this by setting your 'under-relaxation factor'. Make it smaller. Hope this short reply would solve your problems. Regards, Raditya

January 21, 2010, 02:37		#3
usst139 New Member xuusst Join Date: Jan 2010 Posts: 4 Rep Power: 16	Thank you for your kind advice,Raditya Yes,the blade in my model has a very high skewness,so I 'm trying to use the Boundary Layer or Sizefunction to make a better mesh