Residuals converged but high

September 30, 2008, 15:17

Hello CFD users ! I'm running a simulation over a 3D-Wing at 50m/s in a free stream. I use the SST-transition model. My solution converges but the RMS residuals are too high (about 1e-4), furthermore, I checked the lift and drag on the wing and it converges as well. Do I have the right solution ?

Thanks for your help

Gilles

September 30, 2008, 15:19

If the residuals are high it is not converged. Converged means the residuals are sufficiently low, not that they have stopped going down.

Check the solution for regions of instability. Increasing your timestep may help (try a factor of 10). Also, check the mesh for regions of low quality and fix them if necessary.

-CycLone

September 30, 2008, 20:05

Try this page:

http://www.cfd-online.com/Wiki/Ansys...gence_criteria

Glenn Horrocks

September 30, 2008, 15:17	Residuals converged but high	#1
Gilles Guest Posts: n/a	Hello CFD users ! I'm running a simulation over a 3D-Wing at 50m/s in a free stream. I use the SST-transition model. My solution converges but the RMS residuals are too high (about 1e-4), furthermore, I checked the lift and drag on the wing and it converges as well. Do I have the right solution ? Thanks for your help Gilles

September 30, 2008, 15:19	Re: Residuals converged but high	#2
CycLone Guest Posts: n/a	If the residuals are high it is not converged. Converged means the residuals are sufficiently low, not that they have stopped going down. Check the solution for regions of instability. Increasing your timestep may help (try a factor of 10). Also, check the mesh for regions of low quality and fix them if necessary. -CycLone

September 30, 2008, 20:05	Re: Residuals converged but high	#3
Glenn Horrocks Guest Posts: n/a	Try this page: http://www.cfd-online.com/Wiki/Ansys...gence_criteria Glenn Horrocks

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