[tusin111]

Hello, I'm Korean, so I can't speak English well. Please understand that part.
I know that fvm does discretization based on the geometric information on the face as it goes through the cell loop.

Also, as far as I know, the normalvector of the face should point outward.

Here's what I'm wondering
For example, suppose there is a face adjacent to cell 0 and number 1, and let that face be called face 0.

Then the normalvector of face 0 of cell 0 and
Is the normalvector value of face 1 of cell 1 the same?

I'm having a very hard time with this problem, please give me the answer!

[sbaffini]

Here it is how it works:

- you loop on faces, not cells

- for each face your data structure will have the two neighbor cells and a face normal

- the normal as stored in the data structure necessarily goes out of one cell and enters the other

- one typically follows a convention here, say, the first stored cell is the one that has the normal exiting

- when looping on faces for the fluxes, you get the two neighbor cells from the data structure, compute the flux with the stored normal, assign it to the first cell, assign it with a reversed sign to the second cell, because the normal in the fv method is always exiting the cell

It's just that easy