Hello,

I’ve been given an LBM code and I cannot understand what kind of bounceback condition is this:

```
if (obst(x,y,z)) then
c
c...........rotate all ensities and write back to node
node(1,x,y,z) = n_hlp(3,x,y,z)
node(2,x,y,z) = n_hlp(4,x,y,z)
node(3,x,y,z) = n_hlp(1,x,y,z)
node(4,x,y,z) = n_hlp(2,x,y,z)
node(5,x,y,z) = n_hlp(6,x,y,z)
node(6,x,y,z) = n_hlp(5,x,y,z)
node(7,x,y,z) = n_hlp(9,x,y,z)
node(8,x,y,z) = n_hlp(10,x,y,z)
node(9,x,y,z) = n_hlp(7,x,y,z)
node(10,x,y,z) = n_hlp(8,x,y,z)
node(11,x,y,z) = n_hlp(13,x,y,z)
node(12,x,y,z) = n_hlp(14,x,y,z)
node(13,x,y,z) = n_hlp(11,x,y,z)
node(14,x,y,z) = n_hlp(12,x,y,z)
node(15,x,y,z) = n_hlp(17,x,y,z)
node(16,x,y,z) = n_hlp(18,x,y,z)
node(17,x,y,z) = n_hlp(15,x,y,z)
node(18,x,y,z) = n_hlp(16,x,y,z)
```

I was reading boundary review and I couldn’t find it. I think it is not really well implemented, have you got any idea?

Thank you

Antonio