Reply To: Manipulating populations with postprocessors on GPU

[jmctighe]

The boundary condition I am trying to implement is a periodic condition which enforces a constant shear rate across the domain. For a given boundary cell at position x_t, the point in the flow at the other side of the domain the cell needs to reference is time dependent, given by x_m = [mod(x_t + S*L_y*t,L_x),L_y,z_t], where S is the shear rate (S=du/dy), L_x and L_y are the respective x and y dimensions of the domain, and z_t is the z position of the given cell. The populations are then linearly interpolated at point x_m since it does not necessarily fall on a lattice node. Figure 2 in Peng, Wu, Wang, and Li (2023) gives a sketch of this procedure. The final steps involve taking a Galilean transformation of the populations and copying them to the boundary cell before executing the collision step.