BDY Mod

[AMLattanzi]

Modify BDY Nudging

This PR changes how the BDY nudging is completed. Overall, the Laplacian stencil is removed, all of the bdy points are used for nudging, and the w velocity is copied from outside the nudging regions through the nudging region and into the domain ghost cells.

Notes

Idealized tests cases show that nudging with a stratified fluid will yield changes in the density that have non-linear pressure gradient effects. These effects have significant impact on the w velocity inside the bdy region. We now copy the w velocity from outside the bdy region into the bdy region and the ghost cells. This allows us to retain the needed later pressure gradient to force u & v but do not end up with erroneous w from dp/dz that was causing issues.

Simplified test

Laterally forcing u & v from an IC of 0 to 1 at the next time stamp yields:
50 steps at dt=4s

200 steps at dt=4s