The geometry and the lattice size relation

[ztdepztdep]

If i set a 128128 lattice size box for the lid-driven cavity. Does it mean the real geometry size of the cavity is 127127. and the border of the cavity is useless for the results visualization.

[llaniewski]

It depends on your setup. but if you have bounce back boundary conditions on both sides, then you'll have 126x126 real domain.

[ztdepztdep]

Does it mean the computation node is located in the cell center?

[llaniewski]

Yes.

Bounce Back boundary condition corresponds to a boundary half-way between two nodes. So if you have:
BCCCCCB
with B=Bounce Back, and C=Collision, you'll end up with 5 units distance between walls.