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Axisymmetric simpleFoam convergence issues

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Old   August 3, 2016, 13:23
Default Axisymmetric simpleFoam convergence issues
  #1
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Graham
Join Date: Feb 2016
Posts: 5
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Hi there,

I am using simpleFoam to simulate axisymmetric flow in a channel. I cannot get my solution to converge because the solver tries to solve for the third velocity component (Uz) unsuccesfully (residuals attached as pdf).

I have found previous posts on this such as:

http://www.cfd-online.com/Forums/ope...component.html

and

http://www.cfd-online.com/Forums/ope...ric-cases.html

However, there appears to be no fix for this unless I manually force the solver to avoid solving for Uz (which I don't know how to do). This seems surprising for such a simple case!

Does anyone know how to get around this?

My blockMeshDict looks like:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.7.0 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;


L 10.0;
zvalp 0.1;
zvaln -0.1;
yval 0.994987;



vertices
(
(0 0 0)
($L 0 0)
(0 $yval $zvaln)
($L $yval $zvaln)
($L $yval $zvalp)
(0 $yval $zvalp)
);

blocks
(
hex (0 1 3 2 0 1 4 5) (50 50 1) simpleGrading (1 0.1 1) //switch x and y
);

edges
(
arc 2 5 (0 1.0 0)
arc 3 4 ($L 1.0 0)
);


boundary
(
front
{
type wedge;
faces
(
(0 1 4 5)
);
}
back
{
type wedge;
faces
(
(0 1 3 2)
);
}
tankWall
{
type wall;
faces
(
(2 3 4 5)
);
}
inlet
{
type patch;
faces
(
(0 2 5 0)
);
}
outlet
{
type patch;
faces
(
(1 3 4 1)
);
}
axis
{
type empty;
faces
(
(0 1 1 0)
);
}
);

mergePatchPairs
(
);

// ************************************************** *********************** //
Attached Files
File Type: pdf residuals.pdf (48.0 KB, 3 views)
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Old   August 14, 2016, 08:42
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  #2
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Artur
Join Date: May 2013
Location: Southampton, UK
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Hi,

Have you tried the wedge boundary condition? It's explained here:
http://cfd.direct/openfoam/user-guide/boundaries/

All the best,

A
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Old   August 15, 2016, 06:47
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Graham
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Dear Artur,

I am already using the wedge boundary condition - see blockMeshDict above.

Any other suggestions?

Best regards,
Graham
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