[CfdIntro]

Hi,

I'm trying to convert a rectangular mesh to a curved one by using the "arc" selection.

The blockmesh of the curved mesh is:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.4.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}

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

convertToMeters 1;

vertices
(
    
    (-2 -0.75 -0.8)//0
    (1 -0.75 -0.8)//1
    (1  1  -0.8)//2
    (-2 1 -0.8)//3
//
    (-4.1 -0.75 -0.8)//4
    (3.1 -0.75 -0.8)//5
    (3.1 1 -0.8)//6
    (-4.1 1 -0.8)//7

);

blocks
(
    hex (0 1 2 3 4 5 6 7) (30 10 20) simpleGrading (1 1 1)
);

edges
(
    arc 2 3 (-0.5 1 0.25) 
    arc 1 0 (-0.5 -0.75 0.25)
    arc 5 4 (-0.5 -0.75 2.35)
    arc 6 7 (-0.5 1 2.35)
);

boundary
(
    inlet
    {
        type patch;
        faces
        (
        (2 6 5 1)
        );
    }
    outlet
    {
        type patch;
        faces
        (
            (3 0 4 7)  
        );
    }
    road
    {
        type wall;
        faces
        (
            (0 1 5 4)
        );
    }
    top
    {
        type wall;
        faces
        (
            (2 3 7 6)
        );
    }
    sides
    {
        type wall;
        faces
        (
            (0 1 2 3)
            (4 5 6 7)
        );
    }

);

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

After I use the blockMesh command, I'm getting this error in the terminal:

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  5.0                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 5.0-dbb428a3a855
Exec   : blockMesh
Date   : May 07 2018
Time   : 14:47:12
PID    : 4352
I/O    : uncollated
Case   : /home/user/Desktop/curvedmesh
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Deleting polyMesh directory
    "/home/user/Desktop/curvedmesh/constant/polyMesh"
Creating block mesh from
    "/home/user/Desktop/curvedmesh/system/blockMeshDict"
Creating block edges
No non-planar block faces defined
Creating topology blocks


--> FOAM FATAL IO ERROR: 
Block hex (0 1 2 3 4 5 6 7) (30 10 20) simpleGrading (1(1) 1(1) 1(1)) has inward-pointing faces
    4(0 4 7 3) 4(1 2 6 5) 4(0 3 2 1) 

file: /home/user/Desktop/curvedmesh/system/blockMeshDict.blocks at line 37.

    From function void Foam::blockDescriptor::check(const Foam::Istream&)
    in file blockDescriptor/blockDescriptor.C at line 89.

FOAM exiting

I've temporarily fixed this issue by assigning -0,79 to the z coordinate of the 4, 5, 6, 7 vertices but then I'm getting an oval-shaped mesh and not a cyclic one.

Any tip on how to make the 4, 5 & 6, 7 points collinear would be great.

- Openfoam v. 5.0
- OS: Ubuntu 17.04

[simrego]

Hi!


Maybe blockMesh can't do it. I hope someone can explain that, but I think blockMesh create the blocks first and then it'll take into account your edges. And since this block has 0 thickness, when it try to create this block, of course it will crash.
But if you use -0.79999999999999 then it's okay, and -0.79999999999999 = -0.8 so it should be fine.
Or you can use 2 blocks and it will be ok.