CFD Online Discussion Forums - [blockMesh] blockMesh pipe problem

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blockMesh pipe problem

Hello All

I am trying to use blockMesh to create a pipe. My blockMeshdict file is shown. It runs and I can see a pretty good cylinder from paraFoam. However, when I checkMesh, it fails.

Code:

  ***Open cells found, max cell openness: 1, number of open cells 330

  <<Writing 330 non closed cells to set nonClosedCells

  <<Writing 120 cells with high aspect ratio to set highAspectRatioCells

    Mesh non-orthogonality Max: 180 average: 35.0101

 ***Number of non-orthogonality errors: 801.

  <<Writing 801 non-orthogonal faces to set nonOrthoFaces

 ***Error in face pyramids: 1620 faces are incorrectly oriented.

  <<Writing 819 faces with incorrect orientation to set wrongOrientedFaces

Code:

/*--------------------------------*- 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;



vertices

(

// pipe centerl octagon

(0 0 0) // 0

(1 0 0) // 1

(1 0.05 0) // 2

(0 0.05 0) // 3

(0 0 0.05) // 4

(1 0 0.05) // 5

(1 0.0353553 0.0353553) // 6

(0 0.0353553 0.0353553) // 7

(0 0 -0.05) //8

(1 0 -0.05) //9

(1 0.0353553 -0.0353553) //10

(0 0.0353553 -0.0353553) //11

(0 -0.05 0)  //12

(1 -0.05 0) // 13

(1 -0.0353553 -0.0353553) // 14

(0 -0.0353553 -0.0353553) // 15

(0 -0.0353553 0.0353553) // 16

(1 -0.0353553 0.0353553) // 17

// outer octagon

(0 0 0.1) // 18

(1 0 0.1) // 19

(1 0.0707107 0.0707107) // 20

(0 0.0707107 0.0707107) // 21

(0 0.1 0) //22

(1 0.1 0) //23

(0 0.0707107 -0.0707107) // 24

(1 0.0707107 -0.0707107) // 25

(1 0 -0.1) // 26

(0 0 -0.1)// 27

(0 -0.1 0) // 28

(1 -0.1 0) // 29

(1 -0.0707107 -0.0707107) // 30

(0 -0.0707107 -0.0707107) // 31

(0 -0.0707107 0.0707107) //32

(1 -0.0707107 0.0707107) // 33

);



blocks

(

// center up right block

hex (0 1 2 3 4 5 6 7) (30 3 3) simpleGrading (1 1 1)

// center up left block

hex (8 9 10 11 0 1 2 3) (30 3 3) simpleGrading (1 1 1)

// center down left block

hex (15 14 9 8 12 13 1 0) (30 3 3) simpleGrading (1 1 1)

// center down right block

hex (16 17 5 4 12 13 1 0) (30 3 3) simpleGrading (1 1 1)

// outer up right lower block

hex (4 5 6 7 18 19 20 21) (30 3 3) simpleGrading (1 1 1)

// outer up right higher block

hex (3 2 23 22 7 6 20 21) (30 3 3) simpleGrading (1 1 1)

// outer up left higher block

hex (11 10 25 24 3 2 23 22) (30 3 3) simpleGrading (1 1 1)

// outer up left lower block

hex (27 26 25 24 8 9 10 11) (30 3 3) simpleGrading (1 1 1)

// outer down left higher block

hex (31 30 26 27 15 14 9 8) (30 3 3) simpleGrading (1 1 1)

//outer donw left lower block

hex (31 30 14 15 28 29 13 12) (30 3 3) simpleGrading (1 1 1)

//outer donw right lower block

hex (28 29 13 12 32 33 17 16) (30 3 3) simpleGrading (1 1 1)

//outer donw right higher block

hex (32 33 17 16 18 19 5 4) (30 3 3) simpleGrading (1 1 1)

);



edges

(

// at inlet

arc 18 21 (0 0.038269 0.092388)

arc 21 22 (0 0.092388 0.038269)

arc 22 24 (0 0.092388 -0.038269)

arc 24 27 (0 0.038269 -0.092388)

arc 27 31 (0 -0.038269 -0.092388)

arc 31 28 (0 -0.092388 -0.038269)

arc 28 32 (0 -0.092388 0.038269)

arc 32 18 (0 -0.038269 0.092388)



// at outlet

arc 19 20 (1 0.038269 0.092388)

arc 20 23 (1 0.092388 0.038269)

arc 23 25 (1 0.092388 -0.038269)

arc 25 26 (1 0.038269 -0.092388)

arc 26 30 (1 -0.038269 -0.092388)

arc 30 29 (1 -0.092388 -0.038269)

arc 29 33 (1 -0.092388 0.038269)

arc 33 19 (1 -0.038269 0.092388)



);





patches

(



patch inlet

(

(4 7 3 0)

(0 3 11 8)

(0 8 15 12)

(4 0 12 16)



(21 7 4 18)

(22 3 7 21)



(24 11 3 22)

(27 8 11 24)



(31 15 8 27)

(28 12 15 31)



(12 28 32 16)

(16 32 18 4)

)

patch outlet

(

(1 2 6 5)

(9 10 2 1)

(13 1 9 14)

(5 1 13 17)



(5 6 20 19)

(2 23 20 6)



(10 25 23 2)

(26 9 10 25)



(30 14 9 26)

(29 13 14 30)



(33 17 13 29)

(19 5 17 33)

)

wall wall

(

//(4 5 6 7)

//(7 6 2 3)



(18 19 20 21)

(21 20 23 22)



//(3 2 23 22)



(22 23 25 24)

(24 25 26 27)



//(3 2 10 11)

//(11 10 9 8)



//(27 26 9 8)

//(4 5 19 18)



(27 26 30 31)

(31 30 29 28)



//(8 9 14 15)

//(15 14 13 12)



//(28 29 13 12)

//(4 5 19 18)



//(12 13 17 16)

//(16 17 5 4)

(28 29 33 32)

(32 33 19 18)



)



);



mergePatchPairs

(

);



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

Can anyone tell me what seems to be the problem?

thank.

I figured it out. It was a ordering problem for one of the blocks that I have. as always, usually it is the block ordering problem.

Quote:

Originally Posted by xiyuqiu (Post 411826)

I figured it out. It was a ordering problem for one of the blocks that I have. as always, usually it is the block ordering problem.

Quick tip: First released in OpenFOAM 2.0, you can run paraFoam with the following option:

Code:

paraFoam -block

It can help you with figuring out where the ordering might go wrong!

Cylinder BlockMesh

Quote:

Originally Posted by xiyuqiu (Post 411815)

Hello All

I am trying to use blockMesh to create a pipe. My blockMeshdict file is shown. It runs and I can see a pretty good cylinder from paraFoam. However, when I checkMesh, it fails.

Code:

  ***Open cells found, max cell openness: 1, number of open cells 330

  <<Writing 330 non closed cells to set nonClosedCells

  <<Writing 120 cells with high aspect ratio to set highAspectRatioCells

    Mesh non-orthogonality Max: 180 average: 35.0101

 ***Number of non-orthogonality errors: 801.

  <<Writing 801 non-orthogonal faces to set nonOrthoFaces

 ***Error in face pyramids: 1620 faces are incorrectly oriented.

  <<Writing 819 faces with incorrect orientation to set wrongOrientedFaces

Code:

/*--------------------------------*- 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;



vertices

(

// pipe centerl octagon

(0 0 0) // 0

(1 0 0) // 1

(1 0.05 0) // 2

(0 0.05 0) // 3

(0 0 0.05) // 4

(1 0 0.05) // 5

(1 0.0353553 0.0353553) // 6

(0 0.0353553 0.0353553) // 7

(0 0 -0.05) //8

(1 0 -0.05) //9

(1 0.0353553 -0.0353553) //10

(0 0.0353553 -0.0353553) //11

(0 -0.05 0)  //12

(1 -0.05 0) // 13

(1 -0.0353553 -0.0353553) // 14

(0 -0.0353553 -0.0353553) // 15

(0 -0.0353553 0.0353553) // 16

(1 -0.0353553 0.0353553) // 17

// outer octagon

(0 0 0.1) // 18

(1 0 0.1) // 19

(1 0.0707107 0.0707107) // 20

(0 0.0707107 0.0707107) // 21

(0 0.1 0) //22

(1 0.1 0) //23

(0 0.0707107 -0.0707107) // 24

(1 0.0707107 -0.0707107) // 25

(1 0 -0.1) // 26

(0 0 -0.1)// 27

(0 -0.1 0) // 28

(1 -0.1 0) // 29

(1 -0.0707107 -0.0707107) // 30

(0 -0.0707107 -0.0707107) // 31

(0 -0.0707107 0.0707107) //32

(1 -0.0707107 0.0707107) // 33

);



blocks

(

// center up right block

hex (0 1 2 3 4 5 6 7) (30 3 3) simpleGrading (1 1 1)

// center up left block

hex (8 9 10 11 0 1 2 3) (30 3 3) simpleGrading (1 1 1)

// center down left block

hex (15 14 9 8 12 13 1 0) (30 3 3) simpleGrading (1 1 1)

// center down right block

hex (16 17 5 4 12 13 1 0) (30 3 3) simpleGrading (1 1 1)

// outer up right lower block

hex (4 5 6 7 18 19 20 21) (30 3 3) simpleGrading (1 1 1)

// outer up right higher block

hex (3 2 23 22 7 6 20 21) (30 3 3) simpleGrading (1 1 1)

// outer up left higher block

hex (11 10 25 24 3 2 23 22) (30 3 3) simpleGrading (1 1 1)

// outer up left lower block

hex (27 26 25 24 8 9 10 11) (30 3 3) simpleGrading (1 1 1)

// outer down left higher block

hex (31 30 26 27 15 14 9 8) (30 3 3) simpleGrading (1 1 1)

//outer donw left lower block

hex (31 30 14 15 28 29 13 12) (30 3 3) simpleGrading (1 1 1)

//outer donw right lower block

hex (28 29 13 12 32 33 17 16) (30 3 3) simpleGrading (1 1 1)

//outer donw right higher block

hex (32 33 17 16 18 19 5 4) (30 3 3) simpleGrading (1 1 1)

);



edges

(

// at inlet

arc 18 21 (0 0.038269 0.092388)

arc 21 22 (0 0.092388 0.038269)

arc 22 24 (0 0.092388 -0.038269)

arc 24 27 (0 0.038269 -0.092388)

arc 27 31 (0 -0.038269 -0.092388)

arc 31 28 (0 -0.092388 -0.038269)

arc 28 32 (0 -0.092388 0.038269)

arc 32 18 (0 -0.038269 0.092388)



// at outlet

arc 19 20 (1 0.038269 0.092388)

arc 20 23 (1 0.092388 0.038269)

arc 23 25 (1 0.092388 -0.038269)

arc 25 26 (1 0.038269 -0.092388)

arc 26 30 (1 -0.038269 -0.092388)

arc 30 29 (1 -0.092388 -0.038269)

arc 29 33 (1 -0.092388 0.038269)

arc 33 19 (1 -0.038269 0.092388)



);





patches

(



patch inlet

(

(4 7 3 0)

(0 3 11 8)

(0 8 15 12)

(4 0 12 16)



(21 7 4 18)

(22 3 7 21)



(24 11 3 22)

(27 8 11 24)



(31 15 8 27)

(28 12 15 31)



(12 28 32 16)

(16 32 18 4)

)

patch outlet

(

(1 2 6 5)

(9 10 2 1)

(13 1 9 14)

(5 1 13 17)



(5 6 20 19)

(2 23 20 6)



(10 25 23 2)

(26 9 10 25)



(30 14 9 26)

(29 13 14 30)



(33 17 13 29)

(19 5 17 33)

)

wall wall

(

//(4 5 6 7)

//(7 6 2 3)



(18 19 20 21)

(21 20 23 22)



//(3 2 23 22)



(22 23 25 24)

(24 25 26 27)



//(3 2 10 11)

//(11 10 9 8)



//(27 26 9 8)

//(4 5 19 18)



(27 26 30 31)

(31 30 29 28)



//(8 9 14 15)

//(15 14 13 12)



//(28 29 13 12)

//(4 5 19 18)



//(12 13 17 16)

//(16 17 5 4)

(28 29 33 32)

(32 33 19 18)



)



);



mergePatchPairs

(

);



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

Can anyone tell me what seems to be the problem?

thank.

How you calculated the arcs? thank you

Hi,

I have some questions. What are your dimensions for pipe mesh? I mean what is your pipe diameter and length that you used for mesh? I have a pipe mesh problem it has D=4.5 mm and L=970 mm. Could you help me about these questions?

Thank you.

Hi, sorry for the delay of my reply. are you working with snappyHexMesh? mine is D=0.26m and L=0.56m, these are the dimensions of the outer pipe, it has another cylinder in it, it's kind of concentric cylinder. I have worked with a STL file

regards

Quote:

Originally Posted by cesarjets (Post 502378)

Hi Cesarjets,

I do not use snappyHexmESH but, I want to learn and use it as soon as possible.If possible, could you please share your mesh? I think, it will be a good start for me.

Thank you