Navid C. Constantinou

> Damn, I thought we were about to merge too It stops at `CATKEVerticalDiffusivity`...

I'm really confused with this one...

@tomchor I believe that until https://github.com/CliMA/Oceananigans.jl/pull/1024 is resolved, `Flat` topologies could be problematic. Perhaps we should resurrect https://github.com/CliMA/Oceananigans.jl/pull/1024? @ali-ramadhan, @glwagner

Well, it's mentioned in [the docs](https://clima.github.io/OceananigansDocumentation/stable/numerical_implementation/finite_volume/).

#1900 brings the finite-volume discussion further up in the Docs/Numerical Implementations.

Well, I think it's way too early. CATKE is at such an experimental stage that it's not worth documenting. I'm also trying to use it in a 3D channel simulation....

It's nobody's fault :) But just wanted to clarify the state of the matters at this point ;)

Why though it takes 1.5hrs? Any ideas?

@elise-palethorpe, `MGImplicitFreeSurfaceSolver` needed to be defined first before used as a preconditioned method in PGC. I flipped the order of the include files.

@elise-palethorpe also perhaps change the validation script name as @glwagner suggest?