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defining and connecting two circular pipes using blockMesh

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Old   July 29, 2013, 10:42
Default defining and connecting two circular pipes using blockMesh
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Hale
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Hi,

I'm having trouble in defining two circular pipes that are connected with an angle of 90 degrees using blockMesh.

Is there any tutorials or any example that shows how to define such a L-shaped circular pipe in openfoam?

thanks alot
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Old   July 29, 2013, 17:22
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Yosmcer Mocktai
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You can make this with a block and some edges.
Here are two examples I just made. You can copy it and adapt to your needs:

Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices
(
(0 1.292893219 0.707106781)//0
(0 2.707106781 0.707106781)//1
(0 2.707106781 -0.707106781)//2
(0 1.292893219 -0.707106781)//3
(2.707106781 0 0.707106781)//4
(1.292893219 0 0.707106781)//5
(1.292893219 0 -0.707106781)//6
(2.707106781 0 -0.707106781)//7
);

blocks
(
hex (5 4 7 6 0 1 2 3) (50 50 50) simpleGrading (1 1 1)
);

edges
(
arc 0 1 (0 2 1)
arc 1 2 (0 3 0)
arc 2 3 (0 2 -1)
arc 3 0 (0 1 0)

arc 4 5 (2 0 1)
arc 5 6 (1 0 0)
arc 6 7 (2 0 -1)
arc 7 4 (3 0 0)

arc 0 5 (0.914213563 0.914213563 0.707106781)
arc 3 6 (0.914213563 0.914213563 -0.707106781)
arc 1 4 (1.914213562 1.914213562 0.707106781)
arc 2 7 (1.914213562 1.914213562 -0.707106781)
);

boundary
(

);

mergePatchPairs
(
);

// ************************************************** *********************** /
or

Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 1;

vertices
(
(0 1 0)//0
(0 2 1)//1
(0 3 0)//2
(0 2 -1)//3
(3 0 0)//4
(2 0 1)//5
(1 0 0)//6
(2 0 -1)//7
);

blocks
(
hex (5 4 7 6 1 2 3 0) (50 50 50) simpleGrading (1 1 1)
);

edges
(
arc 0 1 (0 1.292893219 0.707106781)
arc 1 2 (0 2.707106781 0.707106781)
arc 2 3 (0 2.707106781 -0.707106781)
arc 3 0 (0 1.292893219 -0.707106781)

arc 4 5 (2.707106781 0 0.707106781)
arc 5 6 (1.292893219 0 0.707106781)
arc 6 7 (1.292893219 0 -0.707106781)
arc 7 4 (2.707106781 0 -0.707106781)

arc 0 6 (0.707106781 0.707106781 0)
arc 1 5 (1.414213562 1.414213562 1)
arc 2 4 (2.121320344 2.121320344 0)
arc 3 7 (1.414213562 1.414213562 -1)
);

boundary
(

);

mergePatchPairs
(
);

// ************************************************** *********************** //
Theses two edge pipe are are quite similar, but depending of how you made the pipes you want to connect, you may prefer one way to the other.

Theses case are quite general with pipes of radius 1 and small curve radius to 1 too (you may need to not have this curve).
Attached Images
File Type: jpg img.jpg (21.8 KB, 52 views)
File Type: jpg img2.jpg (12.5 KB, 42 views)
File Type: jpg imgsec.jpg (22.1 KB, 43 views)
File Type: jpg imgsec2.jpg (14.2 KB, 41 views)

Last edited by Yosmcer; July 30, 2013 at 04:48.
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Old   July 30, 2013, 05:43
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Hale
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Thank you very much Yosmcer. It was a great help Would you please tell me how you calculated the arc midpionts?
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Old   July 30, 2013, 10:52
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Yosmcer Mocktai
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I used the Pythagoras theorem with the simplified fact that the triangles were isosceles.

So basically, for a radius circle (hypotenuse) of 1, I have sqrt(2)/2.

For more general shapes, you can use trigonometry.

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Old   July 31, 2013, 07:10
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Hale
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Thanks you very much for the explanation.
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