Difference between revisions of "CheckMesh"

Revision as of 20:28, 5 September 2012

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.

5 Source

Hrv

@@ Line 1: / Line 1: @@
-== What is "non-orthogonality"? ==
+==Name==
-Is the line connecting two cell centers across the merged patches normal to the face? It is not, which represents mesh non-orthogonality.
+<tt>checkMesh</tt> - Checks validity of a mesh.
-== What is "skewness"? ==
+{{VersionInfo}}{{Version2.1}}
-Does the line connecting two cell centers across the merged patches go through the center of the face? It does not, which represents skewness.
+==Synopsis==
+checkMesh [OPTIONS]
+==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 [[Tip_Advanced_Time_Selection_Options | 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
+==Output explanation==
+The output will be explained based on the <tt>checkMesh</tt> output for the tutorial <tt>$FOAM_TUTORIALS/incompressible/icoFoam/cavity</tt>.
+. <tt>Mesh statistics</tt>
+    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
+. <tt>Checking topology...</tt>
+    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)
+. <tt>Checking geometry...</tt>
+    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.
+. 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.
 == Source ==