Boundaries can be introduced into the model by initially labelling certain of the lattice sites. Different collision rules are then applied at these sites by the collision operator. No-slip conditions are introduced at a boundary by forcing any particle colliding with the boundary to return along the link on which it approached [21]. Figure 3-6 shows the no-slip boundary conditions for the HPP and FHP models for particles approaching a horizontal boundary.
Figure 3-6: No-Slip boundary conditions at a horizontal boundary
for the HPP and FHP models.