I chose LBM as my project for my simulation course. First of all, this site is super helpful, I appreciate it a lot.
I’ve been through the matlab sample code but have one question remaining. It concerns the derivation of the Zou/He microscopic boundary conditions for the inlet and outlet.
% MICROSCOPIC BOUNDARY CONDITIONS: INLET (Zou/He BC) fIn(2,in,col) = fIn(4,in,col) + 2/3*rho(:,in,col).*ux(:,in,col); fIn(6,in,col) = fIn(8,in,col) + 1/2*(f ....
I read their paper, where it says that it was derived by
[…] use bounceback rule for the non-equilibrium part of the particle distribution normal to
the inlet to find f1 - f(eq)1= f3 - f(eq)3.]
Could somebody explain me why they can do that? To my knowledge and the way bounceback is implemented in the matlab-code, it just switches e_i and does not explicitly refer to the non-equilibrium part?!
Thank you very much