How can I access cells located in the centerline of a channel/pipe
 

Hi Foamers,

For my geometry, i will consider :
- either a channel, i.e water flowing between two plane walls, 2D problem
- or a pipe, 3D problem

I am modeling subcooled nucleate boiling, and for each cell in contact with the walls (that are uniformly heated), i need to access and retrieve parameters of a corresponding cell, located in the bulk liquid (roughly around the centerline of my channel/pipe) but at the same axial location.

I created a patch to identify cells in contact with the walls but i dont know how to access the corresponding cell.

If possible I would like to do it in such a way that it is mesh-independent.
Any help welcome.

Thanks a lot!

/Edouard

Hi Edouard

In my opinion, once you know the axial position of your cell, the radial location depends upon the geometry. considering you have a pipe (implies radial symmetry), you can find the location of your centreline by using mesh bounds.
member function mesh.bounds( ) gives you the (minX, minY, minZ) and (maxX, maxY, maxZ). You can use these coordinates to evaluate the location of centreLine .

With the centreLine location known (in 2D y coordinate, in 3d (y,z) coordinate known), you can then utilize the mesh.findCell(const point&) to find the cell label according to your location along the x-axis i.e. your axial direction.

This way your coding will be mesh independent but not geometry independent.

Hope this helps

Regards
jaswi

Hi Jaswi,

Thank you for your message. Your solution seems quite appropriate to what i want to do. I'll try it and come back to this thread if I encounter problems.
Thanks again.

Best

/Edouard

Hi Jaswi,

Could you tell me if this is correct.

// For all the faces in contact with the wall, i.e in my patch thePatchItself
forAll(thePatchItself,iFace)
{
// identify the cell corresponding to the face in contact with the wall
label iCell = thePatchItself.faceCells()[iFace];

//access the cell center point of this cell
vector iCellCentre = mesh.cellCentres()[iCell];

//get the point at the same axial position but located in the center line
vector bulkPoint(0,iCellCentre.y(),0);

// create a label corresponding to this point
label bulkCell = mesh.findCell(bulkPoint);



I think it s correct but I am not yet very familiar with OpenFOAM so i d like to have your opinion.

Thanks in advance

Best

/Edouard