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-   -   mesh spatial dimension in OpenFOAM (http://www.cfd-online.com/Forums/openfoam-meshing/123783-mesh-spatial-dimension-openfoam.html)

jr33 September 20, 2013 16:53

mesh spatial dimension in OpenFOAM
 
My default mesh geometry length is in 80 mm. For OpenFoam, I scaled the mesh in meters as 0.008 m. Once I import the mesh in OpenFOAM, it is a collection of point coordinates. Now, the location of these points and spatial difference between different points will be the same either if they are in mm or m. I feel spatial unit is arbitrary here?

I want to understand when do I have to scale the geometry in Openfoam and when not?

nimasam September 29, 2013 03:25

Quote:

Originally Posted by jr33 (Post 452821)
My default mesh geometry length is in 80 mm. For OpenFoam, I scaled the mesh in meters as 0.008 m. Once I import the mesh in OpenFOAM, it is a collection of point coordinates. Now, the location of these points and spatial difference between different points will be the same either if they are in mm or m. I feel spatial unit is arbitrary here?

I want to understand when do I have to scale the geometry in Openfoam and when not?

well, when you import your mesh, use checkMesh
then you will see the scale of your geometry, if it differs from what you intended then you can use transformPoints -scale '(x x x)'
where x is your scale.

jr33 October 2, 2013 01:00

Thanks, that helps.

Scram_1 May 23, 2016 11:57

Hey,
I have a question regarding the fluentMeshToFoam command. My geometry is in mm and I've created the mesh in ICEM. Now after doing fluentMeshToFoam pipe.msh I do checkMesh. Now, checkMesh gives the dimensions of the overall bounding box without the units. Are these units in mm since my geometry is in mm? or if I want to convert it into mm should I do transformPoints -scale '(0.001 0.001 0.00)'?

For example, when I go to the scale option in fluent, it asks me the units in which my mesh was created and accordingly scales the mesh. What I mean by scale is, it keeps the numbers the same just changes the units. In openFOAM, when I do checkMesh, it gives me the same dimensions without the units. So I don't know what the units are., whether it is m or mm.
Thanks!!
Ram

Scram_1 May 23, 2016 11:59

I meant transformPoints -scale'(0.001 0.001 0.001)' in the previous post


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