CheckMesh

1 Name

checkMesh - Checks validity of a mesh.

Valid versions:

2 Synopsis

checkMesh [OPTIONS]

3 Description

Checks validity of a mesh

-allGeometry

Include bounding box checks

-allTopology

Include extra topology checks

-noTopology

Skip checking the mesh topology

-noZero

Exclude the 0 directory from the times list

-time RANGES

Select time steps. RANGES follows the time selection rules

-latestTime

Apply only on the latest time available

-constant

Include the constant directory in the times list

-parallel

Run the utility in parallel

-roots "(DIR1 [...DIRN])"

Directories through which the data are distributed

-region NAME

Specify a mesh region by its NAME

-case DIR

Execute the command on the case directory DIR. If not provided, use the current directory

-noFunctionObjects

Skip the execution of the functionObjects

-help

Display the help and exit

4 Output explanation

The output will be explained based on the checkMesh output for the tutorial $FOAM_TUTORIALS/incompressible/icoFoam/cavity.

1. Mesh statistics

   points:           882
   internal points:  0
   faces:            1640
   internal faces:   760
   cells:            400
   boundary patches: 3
   point zones:      0
   face zones:       0
   cell zones:       0

Overall number of cells of each type:
   hexahedra:     400
   prisms:        0
   wedges:        0
   pyramids:      0
   tet wedges:    0
   tetrahedra:    0
   polyhedra:     0

2. Checking topology...

   Boundary definition OK.
   Cell to face addressing OK.
   Point usage OK.
   Upper triangular ordering OK.
   Face vertices OK.
   Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
   Patch               Faces    Points   Surface topology                  
   movingWall          20       42       ok (non-closed singly connected)  
   fixedWalls          60       122      ok (non-closed singly connected)  
   frontAndBack        800      882      ok (non-closed singly connected)  

3. Checking geometry...

   Overall domain bounding box (0 0 0) (0.1 0.1 0.01)
   Mesh (non-empty, non-wedge) directions (1 1 0)
   Mesh (non-empty) directions (1 1 0)
   All edges aligned with or perpendicular to non-empty directions.
   Boundary openness (8.47033e-18 -8.47033e-18 -5.901e-17) OK.
   Max cell openness = 1.35525e-16 OK.
   Max aspect ratio = 1 OK.
   Minimum face area = 2.5e-05. Maximum face area = 5e-05.  Face area magnitudes OK.
   Min volume = 2.5e-07. Max volume = 2.5e-07.  Total volume = 0.0001.  Cell volumes OK.
   Mesh non-orthogonality Max: 0 average: 0
   Non-orthogonality check OK.
   Face pyramids OK.
   Max skewness = 1e-08 OK.
   Coupled point location match (average 0) OK.

4. Conclusion

Mesh OK.

Geometry tests:

• Bounding box

The minimal box that can contain the mesh

• Non-empty, non-wedge directions

(1 1 0) means x and y are not empty neither wedges. But z is empty or wedge.

• Non-empty directions

(1 1 0) means x and y are not empty directions. But z is.

• Aspect ratio

Ratio between the longest and the shortest edges - 1.0 is the best.

• Cell volumes

The difference between min and max should be as small as possible (or the evolution should be as smooth as possible - not check for that)

• Mesh non-orthogonality

Measure the angle between the line connecting two cell centres and the normal of their common face - 0.0 is the best.

• Skewness

Measure the distance between the intersection of the line connecting two cell centres with their common face and the centre of that face - smaller is better.

4.1 Other Explanations

• DxFoam reader update - post #15 - Hrvoje Jasak comments on the topics of non-orthogonality and skewness.