Add a dedicated linear WCNSFV page with links to the relevant sections in linearFV, NS and physics

[GiudGiud]

should be a decent start
refs #31887

[moosebuild]

Job Documentation, step Docs: sync website on 7da9e88 wanted to post the following:

View the site here

This comment will be updated on new commits.

[moosebuild]

Job Documentation on e458713 : invalidated by @GiudGiud

random fail

[lindsayad]

it might be more accurate/clearer to introduce an additional column called "solver" and then discretization would remain just "FV" for the linear FV implementation and solver would be "SIMPLE/PIMPLE"

[GiudGiud]

linearFV is kind of different though, not just the solver? like the base classes for the variables are similar but different
like some items that are "discretization"-related such as "two term expansions" are decided in a different place (variables & kernels) in nonlinearFV and linearFV

[lindsayad]

Those are implementation details that are not relevant to a user. Real differences are things like lagging certain quantities in order to keep them linear. I don't know if that is really a difference in the spatial discretization though. More like a state difference

[GiudGiud]

well we do lag a ton more in linearFV than in Newton. In fact we try not to lag anything in Newton

[GiudGiud]

but that's all tied to the solver / discretization in time rather than in space

the gradients are lagged in linearFV and not FV that's a space-time discretization that is different

[lindsayad]

well we do lag a ton more in linearFV than in Newton. In fact we try not to lag anything in Newton

I know that. That's why I said

Real differences are things like lagging certain quantities in order to keep them linear.

I wrote a very large share of the Newton code. I know how it works.

but that's all tied to the solver / discretization in time rather than in space

Agreed. That's why I said

I don't know if that is really a difference in the spatial discretization though. More like a state difference

If the spatial locations used to evaluate things like a Green-Gauss gradient or the non-orthogonal gradient are the same, then I believe the spatial discretization is the same. If the only difference is that you're indexing into different vectors (states), I don't think that equates to a difference in spatial discretization

[GiudGiud]

The iterative two term expansions are something that are unique to FV.
It is tied to not wanting to lag though

[GiudGiud]

If the spatial locations used to evaluate things like a Green-Gauss gradient or the non-orthogonal gradient are the same, then I believe the spatial discretization is the same.

@grmnptr any differences on that aspect?