inlet outlet Zou He BC involved in Collision loop or not?

Lattice Boltzmann Method LBM: Algorithms
#1

Hi LBMers,

I am starting to learn LBM and trying to write my own lbm code in c.
My question is, should the inlet and outlet boundaries, which has zou he BC, also be involved in the collision loop or not?

Thanks for any advice,
Skywalker

#2

Hi Skywalker,

Yes, Zou/He boundary nodes need to be included in collisions. Excluding them from collisions will affect the density or velocity calculated from the known distribution functions and thus give incorrect results. (For a Zou/He boundary specifying velocity in a lid cavity problem, I’ve observed a lid velocity 40% higher than the specified value when the boundary is not involved in collisions.)

Regards,

Michael