Information & Useful utilities

Nico994396 · February 10, 2023, 15:20

Dear All,
i've a relatively simple question for the Openfoam community:

Is it possible to loop over a specified set of faces and cells that have specified coordinates?
I mean:
Suppose i have a rectangular grid and suppose that i want to iterate over specified cells and faces that have specific coordinates :
At my knowledge one should loop over the the cells, over the INTERNAL faces and over the BOUNDARY FACES and then he should check the coordinate singularly.

Now, does someone know if there is a tool more specific for that?
Thank you.

s1291 · February 11, 2023, 04:20

You may need to use:

Code:

mesh.findCell(position)

to find a cell by its coordinates.

For faces, you probably need to use:

Code:

mesh.findNearestFace(position)

// for boundary faces, use:
mesh.findNearestBoundaryFace(position)

➡️ Another alternative way to select sets of cells and faces is to use the topoSet utility. You can then read those sets within your code.

Nico994396 · February 11, 2023, 12:41

Thank you for your answer!
In general i'm looking for a way to get a "slice" of some points of the domain during the solution process: imagine that you have a rectangular mesh and for every ltime-step you must initialize the vertical field in a certain manner:

The problem is that OpenFoam will loop over all the cells and faces with that function and i think that is not so computationally cheap.

Maybe it will be worth to renumber the cells and the faces ( or creating a sort of key-value which maps my indexes to the indexes of openfoam).
Anyway thanks for your reply

February 10, 2023, 15:20	Information & Useful utilities	#1
Nico994396 New Member Nico Join Date: Feb 2018 Location: Turin Posts: 8 Rep Power: 8	Dear All, i've a relatively simple question for the Openfoam community: Is it possible to loop over a specified set of faces and cells that have specified coordinates? I mean: Suppose i have a rectangular grid and suppose that i want to iterate over specified cells and faces that have specific coordinates : At my knowledge one should loop over the the cells, over the INTERNAL faces and over the BOUNDARY FACES and then he should check the coordinate singularly. Now, does someone know if there is a tool more specific for that? Thank you.

February 11, 2023, 04:20		#2
s1291 Member Join Date: Aug 2017 Location: Algeria Posts: 98 Rep Power: 8	You may need to use: Code: mesh.findCell(position) to find a cell by its coordinates. For faces, you probably need to use: Code: mesh.findNearestFace(position) // for boundary faces, use: mesh.findNearestBoundaryFace(position) ➡️ Another alternative way to select sets of cells and faces is to use the topoSet utility. You can then read those sets within your code. Nico994396 likes this. __________________ "When in doubt, use brute force." -- Ken Thompson

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February 11, 2023, 12:41		#3
Nico994396 New Member Nico Join Date: Feb 2018 Location: Turin Posts: 8 Rep Power: 8	Thank you for your answer! In general i'm looking for a way to get a "slice" of some points of the domain during the solution process: imagine that you have a rectangular mesh and for every ltime-step you must initialize the vertical field in a certain manner: The problem is that OpenFoam will loop over all the cells and faces with that function and i think that is not so computationally cheap. Maybe it will be worth to renumber the cells and the faces ( or creating a sort of key-value which maps my indexes to the indexes of openfoam). Anyway thanks for your reply