[sonGoku]

Hi,
I new to OpenFoam . I am solving a case in which i am heating a piece of ice , and I need to remove the portion which melts. So I need to remove cells whose temp is higher than 273K.
Please suggest me some utility to delete/remove those cells.
Anything helpful is greatly appreciated.
Thank You

[alexeym]

Hi,

Would you like to remove those cells:

- Using post-processing utility?
- During solver run?
- Using pre-processing utility before running another case?

Are these cells located near the boundary of the mesh? Are they located somewhere in the middle?

Your question has LOTS of DoF, so it has LOTS of solutions.

[sonGoku]

Hi Alexey Matveichev,
Thanks for replying
I need to remove those cells during run time calculations

[alexeym]

Hi,

OK. You modify solver: add cycle over temperature field, collect melted cell IDs, then use polyRemoveCell (https://cpp.openfoam.org/v5/classFoa...emoveCell.html) to get rid of cells. You can take a look at $FOAM_SRC/dynamicMesh/layerAdditionRemoval for example of cells removal.

Yet you have to answer several questions:
- What is water freezes, you plan to recreate mesh?
- After cell removal you get new boundary. What BC do you plan to impose on the boundary? Especially if boundary is created inside calculation domain.

[sonGoku]

Hi Alexey Matveichev ,
Thanks for your reply.
Can you please tell how to use polyremovecell and how to get cell id?

As for your questions
In my case water wouldn't freeze back so no need to recreate mesh. And I need to impose the same bc as for previous boundary

[alexeym]

Hi,

I can but I do not want to, since it is you, who needs to remove cells. You have documentation, you have working example (layerAdditionRemoval). I (and other users on the Forum) can help you to resolve problems during implementation.

[sonGoku]

Thnx,
For ur support

[sonGoku]

Alexey Matveichev
can u suGGest where i can find working example of layerAdditionRemoval

[alexeym]

You can find it in OpenFOAM source tree: https://github.com/OpenFOAM/OpenFOAM...dditionRemoval (or you can look at your local copy).

Here is a code to remove cell layer: https://github.com/OpenFOAM/OpenFOAM...oveCellLayer.C. It removes cells depending on size, you need to remove them according to temperature.

[sonGoku]

Alexey Matveichev

I came across removeCells class , which uses polyRemoveCell as a header file , but I am haviG trouble to call it .
How to I call the function(constructor for removeCells ) ?
I entered cell ID as
forAll(del.internalField(),i)
{

if(T.internalField()[i]<273.13)del[i]=0.;
else if( T.internalField()[i]>=273.14)
{ del[i]=0;
Ei[i]=0;
removeCells(i);
}
else del[i]=1.0;
}




but it Gives error that i is of type label but the function expects an arGument of type polyMesh.
So please Guide me on how to proceed

[alexeym]

Hi,

You see, official OpenFOAM API documentation is better, than person on a forum. Take a look at https://cpp.openfoam.org/v5/classFoa...moveCells.html.

removeCells is a class. It is constructed from a mesh. After construction it can perform topological changes to the mesh.

[sonGoku]

thnx for ur reply

[sonGoku]

hi,
Alexey Matveichev
I am using class polyTopoChange and its member function removeCell , my code has compiled but now I am having problem to run my case . I haven't setup any dynamicmesh case before so I don't know how to do it. I am unable to set dynamicmeshDict and don't know if any thing else in needed as well .
So I would appreciate if some guidance can come from ur side.
Thnx

[alexeym]

Hi,

You need dynamicMeshDict, if you plan to run simulation with standard mesh modifiers. Since you are doing mesh modifications yourself, there is no need in this dictionary. So, you set up your case as usual and run it.

[sonGoku]

hi,
thnx for ur reply
I ran it usual way , the simulation began but as soon as it reached the cell to be deleted the solver crashed displaying error
--> FOAM FATAL ERROR:
cell 5399 already marked for removal

From function void Foam polyTopoChange::removeCell(Foam::label, Foam::label)
in file polyTopoChange/polyTopoChange/polyTopoChange.C at line 3001.

FOAM aborting

[alexeym]

Error message is quite clear: you mark the same cell for removal twice. It is not allowed.

[sonGoku]

hi,
can u help me deal with this error
--> FOAM FATAL ERROR:
illegal cell label -1
Valid cell labels are 0 .. 6299

From function void Foam: polyTopoChange::removeCell(Foam::label, Foam::label)

[alexeym]

Hi,

What kind of help do you have in mind? Error message is VERY clear. Do you want me to read it again for you? Do you want to talk about the error? OK. This is error. Errors happen. Do not worry.

I think this thread is counter-productive and has 0 value for the community. Maybe we should stop it.