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-   -   checkMesh Error - Number of regions: 5 (http://www.cfd-online.com/Forums/openfoam-meshing/85925-checkmesh-error-number-regions-5-a.html)

lentschi March 9, 2011 15:33

checkMesh Error - Number of regions: 5
 
Hello everyone,

I have a problem with checkMesh so I hope someone can help me.

At first I created a mesh of a pump, which consists of draftube,runner,guide vanes, spiral casing and nose part. These 5 sub-meshes are connected with each other by ggi (in CFX).
Then I exported only the mesh as CGNS and converted it into a foam-compatible-one with cgnsToFoam.

Now, CheckMesh visualises following Log:

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM Extend Project: Open source CFD |
| \\ / O peration | Version: 1.6-ext |
| \\ / A nd | Web: www.extend-project.de |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 1.6-ext
Exec : checkMesh
Date : Mar 09 2011
Time : 15:38:31
SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).

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

Create polyMesh for time = 0

Time = 0

Mesh stats
points: 13415417
faces: 39084423
internal faces: 37938651
cells: 12837179
boundary patches: 17
point zones: 0
face zones: 0
cell zones: 1

Overall number of cells of each type:
hexahedra: 12837179
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
*Number of regions: 5
The mesh has multiple regions which are not connected by any face.
<<Writing region information to "0/cellToRegion"


Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology
DT_to_RU_Side_1 6720 6817 ok (non-closed singly connected)
DT_to_RU_Side_2 24057 24301 ok (non-closed singly connected)
Inflow 8620 8742 ok (non-closed singly connected)
NOSE_LOWER_Side_1 6698 6930 ok (non-closed singly connected)
NOSE_LOWER_Side_2 6732 6965 ok (non-closed singly connected)
NOSE_UPPER_Side_1 6698 6930 ok (non-closed singly connected)
NOSE_UPPER_Side_2 6800 7035 ok (non-closed singly connected)
Outflow 5126 5240 ok (non-closed singly connected)
RU_to_SVWG_Side_1 16524 17010 ok (non-closed singly connected)
RU_to_SVWG_Side_2 32708 33740 ok (non-closed singly connected)
SVWG_to_SC_Side_1 38624 39865 ok (non-closed singly connected)
SVWG_to_SC_Side_2 17600 18003 ok (non-closed singly connected)
WallRot_RU 161829 162541 ok (non-closed singly connected)
WallStat_DT 60370 60585 ok (non-closed singly connected)
WallStat_RU 28674 30132 ok (non-closed singly connected)
WallStat_SC 75666 76181 ok (non-closed singly connected)
WallStat_SVWG 642326 645167 ok (non-closed singly connected)

Checking geometry...
This is a 3-D mesh
Overall domain bounding box (-0.551782 -0.722608 -1.13494) (2.40857 0.611412 0.21191)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Mesh (non-empty, non-wedge) dimensions 3
Boundary openness (-6.81145e-16 -5.32293e-16 1.79185e-17) Threshold = 1e-06 OK.
***High aspect ratio cells found, Max aspect ratio: 1483.03, number of cells 3629 Threshold = 1000
Writing 3629 cells with high aspect ratio to set highAspectRatioCells
Minumum face area = 5.68587e-10. Maximum face area = 0.000732129. Face area magnitudes OK.
Min volume = 1.11295e-13. Max volume = 6.52634e-06. Total volume = 1.18124. Cell volumes OK.
Mesh non-orthogonality Max: 79.6113 average: 23.0032 Threshold = 70
*Number of severely non-orthogonal faces: 132299.
Non-orthogonality check OK.
Writing 132299 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 3.70244 OK.

Failed 1 mesh checks.

End


The high aspect ratio is no problem because I get a finer mesh too, which inhibit this warning (or is this warning the visualised error??).
But I do not know how to eliminate the Error "Number of regions: 5
The mesh has multiple regions which are not connected by any face.

Why are there 5 disconnect regions?...I adapted my "boundary" file in the constant/polymesh directory to define all boundaries and connected the sub-meshes with each other by ggi.

Here is my boundary file:


/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM Extend Project: Open source CFD |
| \\ / O peration | Version: 1.6-ext |
| \\ / A nd | Web: www.extend-project.de |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format binary;
class polyBoundaryMesh;
location "constant/polyMesh";
object boundary;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

17
(
DT_to_RU_Side_1
{
type ggi;
nFaces 6720;
startFace 37938651;
shadowPatch DT_to_RU_Side_2;
zone DT_to_RU_Side_1_Zone;
bridgeOverlap false;
}
DT_to_RU_Side_2
{
type ggi;
nFaces 24057;
startFace 37945371;
shadowPatch DT_to_RU_Side_1;
zone DT_to_RU_Side_2_Zone;
bridgeOverlap false;
}
Inflow
{
type patch;
nFaces 8620;
startFace 37969428;
}
NOSE_LOWER_Side_1
{
type ggi;
nFaces 6698;
startFace 37978048;
shadowPatch NOSE_LOWER_Side_2;
zone NOSE_LOWER_Side_1_Zone;
bridgeOverlap false;
}
NOSE_LOWER_Side_2
{
type ggi;
nFaces 6732;
startFace 37984746;
shadowPatch NOSE_LOWER_Side_1;
zone NOSE_LOWER_Side_2_Zone;
bridgeOverlap false;
}
NOSE_UPPER_Side_1
{
type ggi;
nFaces 6698;
startFace 37991478;
shadowPatch NOSE_UPPER_Side_2;
zone NOSE_UPPER_Side_1_Zone;
bridgeOverlap false;
}
NOSE_UPPER_Side_2
{
type ggi;
nFaces 6800;
startFace 37998176;
shadowPatch NOSE_UPPER_Side_1;
zone NOSE_UPPER_Side_2_Zone;
bridgeOverlap false;
}
Outflow
{
type patch;
nFaces 5126;
startFace 38004976;
}
RU_to_SVWG_Side_1
{
type ggi;
nFaces 16524;
startFace 38010102;
shadowPatch RU_to_SVWG_Side_2;
zone RU_to_SVWG_Side_1_Zone;
bridgeOverlap false;
}
RU_to_SVWG_Side_2
{
type ggi;
nFaces 32708;
startFace 38026626;
shadowPatch RU_to_SVWG_Side_1;
zone RU_to_SVWG_Side_2_Zone;
bridgeOverlap false;
}
SVWG_to_SC_Side_1
{
type ggi;
nFaces 38624;
startFace 38059334;
shadowPatch SVWG_to_SC_Side_2;
zone SVWG_to_SC_Side_1_Zone;
bridgeOverlap false;
}
SVWG_to_SC_Side_2
{
type ggi;
nFaces 17600;
startFace 38097958;
shadowPatch SVWG_to_SC_Side_1;
zone SVWG_to_SC_Side_2_Zone;
bridgeOverlap false;
}
WallRot_RU
{
type wall;
nFaces 161829;
startFace 38115558;
}
WallStat_DT
{
type wall;
nFaces 60370;
startFace 38277387;
}
WallStat_RU
{
type wall;
nFaces 28674;
startFace 38337757;
}
WallStat_SC
{
type wall;
nFaces 75666;
startFace 38366431;
}
WallStat_SVWG
{
type wall;
nFaces 642326;
startFace 38442097;
}
)

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

Can anyone tell me how to eliminate this error or can give me some tips?:confused:


Thanks in advance.

Regards Markus

lentschi March 11, 2011 05:35

No problem - the separated regions are only warnings!


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