[elisenda]

Dear all,

I am trying to mesh an stl geometry with snappyHexMesh. I can see that the feature lines (or edges) I have in the geometry are omitted. The mesh don't follows the lines.

I would like to use the someLine.eMesh file but I don't know their format and I don't know where I have to place it into the structure directories.

I don't know if this is a good way but I have not other ideas.

1) Can anybody help me how to use and how to generate the someLine.eMesh file?
2) Have anybody any other ideas?

Thanks in advance,
Elisenda

[Wolle]

Hi Elisenda,

Is that what you mean by "feature lines/edges are omitted"?

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

There are some other threads about that in the forum, but I (not experienced at all!) think, there's no solution to that problem at the moment.

I don't know, whether the someLine.eMesh approach is adequate for this kind of problem, but would be interested too. Anyway I didn't read anything about that yet and came across these settings just today...

Cheers
Wolle

[elisenda]

Hello Wolle,

This is exactly what I mean.
I think the eMesh file can help me. I am not sure but I would like to try.
The problem is that I don't know their format.

Has anybody idea about the eMesh format?

[norman1981]

Originally Posted by elisenda

Has anybody idea about the eMesh format?

Hi!
Look at the iglooWithFridges/constant/triSurface/fridgeA.eMesh file:

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: http://www.openfoam.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

FoamFile
{
version 2.0;
format ascii;

root "..";
case "cavity";
instance ""constant"";
local "polyMesh";

class featureEdgeMesh;
object points;
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

// Points
(
(1.99 1.99 0.01) //0
(3.01 1.99 0.01) //1
(3.01 3.01 0.01) //2
(1.99 3.01 0.01) //3

(1.99 1.99 2.01) //4
(3.01 1.99 2.01) //5
(3.01 3.01 2.01) //6
(1.99 3.01 2.01) //7
)
// Edges
(
(0 1)
(1 2)
(2 3)
(3 0)

(4 5)
(5 6)
(6 7)
(7 4)

(0 4)
(1 5)
(2 6)
(3 7)
)
// ************************************************** *********************** //

Regards

Norman

[elisenda]

Hi Norman,

Thank you for your very quick answer. I will try with this format.
I will say you if the mesh follows the edges.

Thanks and regards,
Elisenda

[elisenda]

Hi Norman,

I used this format and the snappyHexMesh runs well. The problem is that the mesh don't follows the edges.
I don't know what I can do.

Any suggestions?
Elisenda

[norman1981]

Originally Posted by elisenda

Hi Norman,

Thank you for your very quick answer. I will try with this format.
I will say you if the mesh follows the edges.

Thanks and regards,
Elisenda

You're welcome!
I tried that solution last april and it didn't improve my case so much.. maybe the new snappyHexMesh version works better using these feature lines but I think you'll only get a refinement around your feature lines because the edge capturing is not already implemented in snappyHexMesh :-(
Anyway let me know!

Regards
Norman

[elisenda]

Hi Norman,
I use "level 10" on the edges.eMesh file:

features
(
{
file "edges.eMesh";
level 10;
}
);


and the mesh is refined near the edges. I have a lot of elements. It is not bad, but it would be better follows the edges but without increase the number of elements. It is a pity.

Elisenda

[norman1981]

Hi Elisenda,

I agree but this is the only way to get a grid that follow in some way your edges because at this moment the edge capturing is not implemented in snappyHexMesh.

Norman

[openfoam_user]

Hi Elisenda,

Have you find a way or a 'best strategy' to improve your mesh quality near the edges ?

Best regards,

Stephane

[elisenda]

Stephane,

This is the only way I have found. I don't know if there is another one.