"divergence detected in amg solver ads-0" after improving meshing using TUI commands

harshabose · January 27, 2019, 09:58

mesh orthogonal quality reduced after creating inflation on wing surface.

I used inflation on wing surface according to the Y+ values needed for my problem. This reduced my orthogonal quality to order of e-03. I tried to improve the mesh by using TUI commands and then the orthogonal quality improved to e-01. Was happy with the result but, when I initialized the problem it showed this error.
divergence detected in amg solver ads-0
Then i tried with my original mesh and everything was cool. Does this orthogonal quality even matter? only thing i know about orthogonal quality is that it should be close to 1. Any comments are appreciated.

RcktMan77 · January 28, 2019, 18:54

Yes, it matters and it's a big deal. You want your mesh's cell face normals to be aligned with the flow direction as much as possible in order to reduce numerical error. In your case, the error is destabilizing your problem likely due to poor mesh quality when you attempt to create a boundary layer resolved mesh.

harshabose · January 29, 2019, 10:14

Thanks for the comment. Can you give me tips for getting a good orthogonal quality mesh with inflation?

RcktMan77 · January 29, 2019, 10:51

It sounds like you're using Fluent, which isn't something I use regularly for mesh generation or as my preferred flow solver. Perhaps others here who use those tools can comment.

January 27, 2019, 09:58	"divergence detected in amg solver ads-0" after improving meshing using TUI commands	#1
harshabose New Member Harsha Vardhan Join Date: Jan 2019 Posts: 4 Rep Power: 6	mesh orthogonal quality reduced after creating inflation on wing surface. I used inflation on wing surface according to the Y+ values needed for my problem. This reduced my orthogonal quality to order of e-03. I tried to improve the mesh by using TUI commands and then the orthogonal quality improved to e-01. Was happy with the result but, when I initialized the problem it showed this error. divergence detected in amg solver ads-0 Then i tried with my original mesh and everything was cool. Does this orthogonal quality even matter? only thing i know about orthogonal quality is that it should be close to 1. Any comments are appreciated.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Two Phase Flow In Vertical Pipe	stonepreston	FLUENT	2	October 31, 2017 08:35
Divergence detected in AMG solver: pressure correction	xinquanzhoucn	FLUENT	5	July 21, 2014 04:49
Error: Divergence detected in AMG solver: x-momentum/ epsilon/ temperature	bubuchacha	FLUENT	6	February 26, 2013 03:30
user subroutine error	CFDUSER	CFX	2	December 9, 2006 06:31
user defined function	cfduser	CFX	0	April 29, 2006 10:58

January 28, 2019, 18:54		#2
RcktMan77 Member Zach Davis Join Date: Jan 2010 Location: Huntsville, AL Posts: 98 Rep Power: 15	Yes, it matters and it's a big deal. You want your mesh's cell face normals to be aligned with the flow direction as much as possible in order to reduce numerical error. In your case, the error is destabilizing your problem likely due to poor mesh quality when you attempt to create a boundary layer resolved mesh.

January 29, 2019, 10:14		#3
harshabose New Member Harsha Vardhan Join Date: Jan 2019 Posts: 4 Rep Power: 6	Thanks for the comment. Can you give me tips for getting a good orthogonal quality mesh with inflation?

January 29, 2019, 10:51		#4
RcktMan77 Member Zach Davis Join Date: Jan 2010 Location: Huntsville, AL Posts: 98 Rep Power: 15	It sounds like you're using Fluent, which isn't something I use regularly for mesh generation or as my preferred flow solver. Perhaps others here who use those tools can comment.