[ztdep]

Hello, I write a simple heat conduction solver on square domain with 4x4 grids and the solver can give correct results.
The four sides of the domain have the first kind boundary conditions.

But when I output the matrix coefficients. It seems the matrix diagonal doesn't include the boudnary coefficients?


for(label faceI=0;faceI<TEqn.diag().size(); faceI++)
{
Info<<TEqn.diag()[faceI]<<" "<<faceI<<nl;
}

the output is
-0.2 0
-0.3 1
-0.3 2
-0.2 3
-0.3 4
-0.4 5
-0.4 6
-0.3 7
-0.3 8
-0.4 9
-0.4 10
-0.3 11
-0.2 12
-0.3 13
-0.3 14
-0.2 15
what I have missing?

[Tobi]

A question... what is a 4 x 4 grid for you? Do you have 4 cells or how does it look like? A short picture will give us the answer. It seems you do have 4 cells in one row and 3 cols so 12 cells in total. If this is correct then I can directly give you the answer.

[invadoria]

The following document is useful for the contribution of the boundary conditions to the diagonal term.


https://www.foamacademy.com/wp-conte...2018matrix.pdf