[snappyHexMesh] Average cell size

emma · October 24, 2022, 12:45

Hi,

I have to do a grid convergence study and i need the average cell size (mesh obtained with snappyhexmesh), but i can't figure it out how to do it.
Could someone help me?

Thanks

AtoHM · October 25, 2022, 03:28

1) checkMesh can put out cellVolume field which you can use (-writeAllFields option)

2) Paraview has a filter called mesh quality. This allows you to extract all sorts of quality measures per cell. You can presribe it to put out the cell volume as a field, which you can either export and process somewhere else or make e.g. a histogram in Paraview itself. I remember with this approach, sometimes PV is not able to extract volume (or was it area?) correctly for all cell types, then the result may be off.

MohdShaeq · May 13, 2024, 08:55

Quote:

Originally Posted by emma

Hi,

I have to do a grid convergence study and i need the average cell size (mesh obtained with snappyhexmesh), but i can't figure it out how to do it.
Could someone help me?

Thanks

The average element/cell size can easily be calculated by the following formula:-

$^{E}size$ = $\sqrt[3]{^{V}mesh/^{N}hex}$
where
$^{E}size$ is the average size of an element,
$^{V}mesh$ is the volume of the mesh, and
$^{N}hex$ is the number of hexahedral elements of which the mesh is composed.

The latter two can easily be found out using the checkMesh utility.

The following link explains this procedure in detail:-
https://www.sandia.gov/files/cubit/1...tem/set-up.htm

October 24, 2022, 12:45	Average cell size	#1
emma New Member Join Date: Oct 2022 Posts: 1 Rep Power: 0	Hi, I have to do a grid convergence study and i need the average cell size (mesh obtained with snappyhexmesh), but i can't figure it out how to do it. Could someone help me? Thanks

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October 25, 2022, 03:28		#2
AtoHM Senior Member M Join Date: Dec 2017 Posts: 701 Rep Power: 12	1) checkMesh can put out cellVolume field which you can use (-writeAllFields option) 2) Paraview has a filter called mesh quality. This allows you to extract all sorts of quality measures per cell. You can presribe it to put out the cell volume as a field, which you can either export and process somewhere else or make e.g. a histogram in Paraview itself. I remember with this approach, sometimes PV is not able to extract volume (or was it area?) correctly for all cell types, then the result may be off.