Help! Divergence detected in AMG solver: pressure correction

user0314 · September 2, 2011, 11:11

Hi,

I am running a 3D fluent simulation consisting of a rotating disk with a column of fluid (air) above it. The disk is spinning at 1500 rpm. After 1000 iterations I get the error:

Divergence detected in AMG solver: pressure correction
Primitive error at node 1: floating point exception

I am running a pressure based steady solver.

The BC's are Pressure inlet at the inlet (the top of the column of fluid), pressure outlet at the radial wall surrounding the disk.

Since it seems to be converging until 1000 iterations, is it a mesh problem or is it a BC problem? I tried decreasing the URF for pressure but it doesn't help.

If you need more details let me know.

Thanks.

stuart23 · September 2, 2011, 14:04

What p-v coupling are you using? And which AMG scheme?

user0314 · September 2, 2011, 17:11

P-V coupling:

scheme: simple
gradient: least squares based
pressure: presto
momentum: first order upwind

AMG: pressure-based V-cycle

Thanks.

user0314 · September 2, 2011, 17:12

P-V coupling:

scheme: simple
gradient: least squares based
pressure: presto
momentum: first order upwind

AMG: pressure-based V-cycle

Thanks.

September 2, 2011, 11:11	Help! Divergence detected in AMG solver: pressure correction	#1
user0314 New Member Join Date: May 2011 Posts: 23 Rep Power: 15	Hi, I am running a 3D fluent simulation consisting of a rotating disk with a column of fluid (air) above it. The disk is spinning at 1500 rpm. After 1000 iterations I get the error: Divergence detected in AMG solver: pressure correction Primitive error at node 1: floating point exception I am running a pressure based steady solver. The BC's are Pressure inlet at the inlet (the top of the column of fluid), pressure outlet at the radial wall surrounding the disk. Since it seems to be converging until 1000 iterations, is it a mesh problem or is it a BC problem? I tried decreasing the URF for pressure but it doesn't help. If you need more details let me know. Thanks.

September 2, 2011, 17:11	More information and Reply	#3
user0314 New Member Join Date: May 2011 Posts: 23 Rep Power: 15	P-V coupling: scheme: simple gradient: least squares based pressure: presto momentum: first order upwind AMG: pressure-based V-cycle Thanks.

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September 2, 2011, 14:04		#2
stuart23 Senior Member Stuart Buckingham Join Date: May 2010 Location: United Kingdom Posts: 267 Rep Power: 26	What p-v coupling are you using? And which AMG scheme?

September 2, 2011, 17:12		#4
user0314 New Member Join Date: May 2011 Posts: 23 Rep Power: 15	P-V coupling: scheme: simple gradient: least squares based pressure: presto momentum: first order upwind AMG: pressure-based V-cycle Thanks.