[bojiezhang]

Hello everyone:

I want to find the cells surround one cell "on the boundary", (the cell is face). If I know one face ID, how can I find the faces ID around this face? For example, if the face is quadrangle, I want to find the other 8 faces around it.

Could someone know how to deal with it? Thank you!

bojiezhang

[olesen]

Originally Posted by bojiezhang

Hello everyone:

I want to find the cells surround one cell "on the boundary", (the cell is face). If I know one face ID, how can I find the faces ID around this face? For example, if the face is quadrangle, I want to find the other 8 faces around it.

Could someone know how to deal with it? Thank you!

bojiezhang

Finding the immediate neighbouring faces (eg, 4 neighbouring faces from a quad) shouldn't be too bad:
- from boundary face, get the owner cell
- for this owner cell, get all the associated faces
- get the neighbouring cells from the faces
- loop through to find the which of the neighbour cell faces to find a boundary face.

If you need the "corner" faces, my first approach would be brute force.
- from the boundary face you know the vertices, place them in a labelHashSet.
- loop through the boundary faces and tag each face that shares a vertex with the original face. A labelHashSet of the face Ids might be useful here.

This should work. Instead of looping across all boundary faces, you may want to restrict your search to a particular patch though - for efficency and to avoid finding a neighbour with a different BC treatment.

[Tushar@cfd]

Dear olesen,

Finding the immediate neighbouring faces (eg, 4 neighbouring faces from a quad) shouldn't be too bad:
- from boundary face, get the owner cell
- for this owner cell, get all the associated faces
- get the neighbouring cells from the faces
- loop through to find the which of the neighbour cell faces to find a boundary face.

Thank you for the valuable information.

How to get all the associated faces for the owner cell? I wish to use groovyBC for the same.

[PicklER]

Hello

The function name is bit confusing, but to get the faces of a cell called FaceIOwner:

const cell& facesOfOwner = mesh.cells()[FaceIOwner];

[Tushar@cfd]

Thank you for the info.

-
Best Regards!