checkMesh

checkMesh will check for:

• Mesh statistics
• Topology
• Geometry and mesh quality (bounding box, cell volumes, skewness, orthogonality, aspect ratio, and so on).

To check the most important parameters of the mesh, run the utilities without flags:

checkMesh

If checkMesh explicitly generates an error, this error field must be repaired. To check all the possible measurable parameters of the mesh (often an overkill utilities), and visualise all the fields, run:

checkMesh -allGeometry -allTopology -writeAllFields -writeSets vtk

Most of the time, it is impossible to get no errors when we look at all the mesh fields. A more progmatic way, is to write the field when you encouter an important error, so you can post-process via ParaView your mesh and check all the defective set of cells, faces and/or points written to the constant/polyMesh/sets/ directory with the following flags

checkMesh -writeSets vtk

It will write Sets and cellZones.

Most important mesh parameters

Only few parameters between Settings and Topology must kept under control to produce a sufficient output.

Settings

The most important parameters to keep under control when we deal with mesh genration are:

	Non orthogonality	Skewness
Rapresentation
Limits	Not run a case if it is above 80	Acceptable under 3

Then is very important to check minVolume (if it is negative, check the .stl files or setting)

Topology

To improve the quality of the mesh try to remove as much as possible tetrahedra and tet wedges.

Deletion of bad quality cells

You can delete bad cells if they are not in region of interest, if this is the case, utilities such as setSet and subsetMesh can be useful tools, otherwise it is strongly advised to re-mesh. Instead, deleting mesh arbitrarely is usually done via this utilities.

setSet -constant

An internal command line will appear, and similar command can be used to manage bad cells present in your mesh (i.e. concave, underdetermined, zero volume cells), in the followng commands a zero-volume cells are treated:

# if you want to fix additional cells and with problematic faces you can (i.e. skew, concave, warp faces etc..)
cellSet c0 new cellToCell zeroVolumeCells any
cellSet c0 add faceToCell skewFaces any
cellSet c0 invert && quit

Once exited from the internal command line, execute the following command to overwrite the mesh

subSetMesh c0 -overwrite