# Airfoil Convergence Problem at High Angle of Attack

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July 20, 2022, 10:26
Airfoil Convergence Problem at High Angle of Attack
#1
New Member

Arash
Join Date: Jun 2022
Posts: 4
Rep Power: 2
Hi
I'm simulating an airfoil in range of 0-18 (deg) angle of attack, And I have convergence problem at 16...18 degree.
flow is incompressible,
Geometry is fixed and flow has direction,
K-Omega SST turbulent model at default settings,
Reference values are set (Area = chord length),
Standard initialization from inlet,

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July 20, 2022, 10:50
#2
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Void_CFD-user
Join Date: Feb 2022
Posts: 67
Rep Power: 3
Quote:
 Originally Posted by ArashDi Hi I'm simulating an airfoil in range of 0-18 (deg) angle of attack, And I have convergence problem at 16...18 degree. flow is incompressible, Geometry is fixed and flow has direction, K-Omega SST turbulent model at default settings, Reference values are set (Area = chord length), Standard initialization from inlet,
This doesn't look necessarily diverged, it's just oscillating a lot. Try using coupled scheme with pseudo time step and manage that time step. Also, try using fmg initialisation, it's a better form of initialisation. How does your fluid domain look? Can you attach any contours?

July 21, 2022, 19:19
To some extent done
#3
New Member

Arash
Join Date: Jun 2022
Posts: 4
Rep Power: 2
Quote:
 Originally Posted by Indra This doesn't look necessarily diverged, it's just oscillating a lot. Try using a coupled scheme with a pseudo time step and manage that time step. Also, try using fmg initialization, it's a better form of initialization. How does your fluid domain look? Can you attach any contours?
Hi, Thank you, Indra
It was a meshing problem and I tried to refine the mesh and finally, It was Solved, It was a steady state modeling, Therefore, I was unable to use a pseudo time step, I did it with FMG initialization, But it took much time and iterations.
All the best
Arash

 Tags convergence, divergence, fluent, k-omega sst