[Arjun Jayakumar]

Dear all,

I am new to blockMesh utility. I have attached my domain with corresponding vertices numbering. I want to divide my domain in to four as marked in the figure.
for that following codes are used:

hex(0 1 2 8 10 11 12 18) (10 10 1) simpleGrading (1 1 1) //block 0
hex(8 2 3 7 18 12 13 17) (10 10 1) simpleGrading (1 1 1) //block 1
hex(7 9 5 6 17 19 15 16) (10 10 1) simpleGrading (1 1 1) //block 2
hex(9 3 4 5 19 13 14 15) (10 10 1) simpleGrading (1 1 1) //block 3

But i am getting two internal face, its orientation is (7 17 9 19) and (9 19 3 13)

I want to get rid of this internal face. Or help me with any other condition that will nullify the effect of internal face.
DSC_1749.jpg

[Tushar@cfd]

Originally Posted by Arjun Jayakumar

Dear all,

I am new to blockMesh utility. I have attached my domain with corresponding vertices numbering. I want to divide my domain in to four as marked in the figure.
for that following codes are used:

hex(0 1 2 8 10 11 12 18) (10 10 1) simpleGrading (1 1 1) //block 0
hex(8 2 3 7 18 12 13 17) (10 10 1) simpleGrading (1 1 1) //block 1
hex(7 9 5 6 17 19 15 16) (10 10 1) simpleGrading (1 1 1) //block 2
hex(9 3 4 5 19 13 14 15) (10 10 1) simpleGrading (1 1 1) //block 3

But i am getting two internal face, its orientation is (7 17 9 19) and (9 19 3 13)

I want to get rid of this internal face. Or help me with any other condition that will nullify the effect of internal face.
Attachment 35071

I would rather create blocks out of nodes (9,19) and divide block 0 and 1, similar to block 2 and 3.

Anyways, try defining your Boundary Conditions like this,

defaultFaces
{
type empty;
}

Re-run your case, I hope it will solve your problem.

-
Best Luck!

[Arjun Jayakumar]

Originally Posted by Tushar@cfd

I would rather create blocks out of nodes (9,19) and divide block 0 and 1, similar to block 2 and 3.

Anyways, try defining your Boundary Conditions like this,

defaultFaces
{
type empty;
}

Re-run your case, I hope it will solve your problem.

-
Best Luck!

dear tushar,

thank you for your time.
I have already tried this by setting the defaultfaces to empty but this will not help to solve the problem.
Its showing higher velocities at the patch surface, which result in too high courant number.
Do you know how i am getting these internal faces, without defining any where in the blockMesh dictionary.

[Tushar@cfd]

Originally Posted by Arjun Jayakumar

dear tushar,

thank you for your time.
I have already tried this by setting the defaultfaces to empty but this will not help to solve the problem.
Its showing higher velocities at the patch surface, which result in too high courant number.
Do you know how i am getting these internal faces, without defining any where in the blockMesh dictionary.

Dear Arjun,

The error is in the blockMesh, due to node (9, 19) which is connected to a face. If you remove this node and use only 3 blocks it will work, as it will follows the block rule.

If your case demands such mesh only. Then, you can try "merge" option of OpenFOAM. Although, I never tried it but I think that will help you resolve.

Please, do share to FOAM community if you happen to get correct solutions.

-
Best Luck!

[Arjun Jayakumar]

Originally Posted by Tushar@cfd

Dear Arjun,

The error is in the blockMesh, due to node (9, 19) which is connected to a face. If you remove this node and use only 3 blocks it will work, as it will follows the block rule.

If your case demands such mesh only. Then, you can try "merge" option of OpenFOAM. Although, I never tried it but I think that will help you resolve.

Please, do share to FOAM community if you happen to get correct solutions.

-
Best Luck!

dear tushar,

I need to define a patch on face (4 14 15 5).

If i try with 3 blocks it will lead to error "face 0 in patch 0 does not have neighbour cell face: 4(4 14 15 5).

I am not familiar with merge. which all faces do you suggest to merge.

Thank you

[Tushar@cfd]

Originally Posted by Arjun Jayakumar

dear tushar,

I need to define a patch on face (4 14 15 5).

If i try with 3 blocks it will lead to error "face 0 in patch 0 does not have neighbour cell face: 4(4 14 15 5).

I am not familiar with merge. which all faces do you suggest to merge.

Thank you

Dear Arjun,

You can easily construct 3 block for the case which you have referred in the figure. Follow carefully the blockMesh strategy of OpenFOAM, refer link below for the same:

http://www.openfoam.org/docs/user/blockMesh.php

For merge patch I am not an expert. You can explore it.

-
Best Luck!

[mturcios777]

An alternative method is to generate the 3-block mesh which works, then use topoSet to select the faces that correspond to face 4 14 15 5 and use createPatch to generate the boundary patch.

I've found this approach is more consistent and allows you to make all kinds of boundary patches that only partially cover the domain boundaries, and requires less debugging of the blockMesh dict file which can become a real headache.

[Arjun Jayakumar]

Originally Posted by mturcios777

An alternative method is to generate the 3-block mesh which works, then use topoSet to select the faces that correspond to face 4 14 15 5 and use createPatch to generate the boundary patch.

I've found this approach is more consistent and allows you to make all kinds of boundary patches that only partially cover the domain boundaries, and requires less debugging of the blockMesh dict file which can become a real headache.

Thank you for your suggestion Marco. I think it will take some time for me to familiarize with topoSet utility. Will post the updates and looking forward to your help in future.