Convergence problem caused by wallscale

Roland R · August 16, 2011, 11:02

Hello,

I have read i earlier topics that in some cases the wallscale residual doesn't decrease. I calculate a 2D wing, the quad cells are extruded to one layer which is very thin because of the fine boundary layer elements. So the aspect ratio is not too high. In spite of this the residual of wallscale is not ok. Setting "double precision" was investigated but it didn't help the convergence...

What can cause this rare error?

Thanks
Roland

ghorrocks · August 16, 2011, 19:30

If the wallscale equation does not converge then almost certainly your mesh quality is terrible and the Navier Stokes equations won't converge either. Better fix the mesh quality.

August 16, 2011, 11:02	Convergence problem caused by wallscale	#1
Roland R Senior Member Roland Rakos Join Date: Mar 2009 Posts: 131 Rep Power: 18	Hello, I have read i earlier topics that in some cases the wallscale residual doesn't decrease. I calculate a 2D wing, the quad cells are extruded to one layer which is very thin because of the fine boundary layer elements. So the aspect ratio is not too high. In spite of this the residual of wallscale is not ok. Setting "double precision" was investigated but it didn't help the convergence... What can cause this rare error? Thanks Roland

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August 16, 2011, 19:30		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 18,017 Rep Power: 146	If the wallscale equation does not converge then almost certainly your mesh quality is terrible and the Navier Stokes equations won't converge either. Better fix the mesh quality.