Why is solid_interface used for reducing immersed fields?

[glwagner]

I got a little confused reading

Oceananigans.jl/src/ImmersedBoundaries/immersed_fields_reductions.jl

Line 28 in 4f1fe0f

return get_condition(condition.func, i, j, k, ibg, args...) & !(solid_interface(LX(), LY(), LZ(), i, j, k, ibg))

because I thought that solid_interface was defined for fluxes while solid_node was for masking. Can we clarify what the purpose of these two functions are? Do their names need to be changed?

@simone-silvestri

[simone-silvestri]

This issue is connected to #2249.

Since we use solid_interface to mask a field, we use the same function to reduce the field.
solid_interface is used for masking because we want to mask up to the interface to ensure impenetrability.
For a scalar in the context of a GridFittedBoundary solid_interface and solid_node are equivalent

Maybe, in view of the new PartialCellBoundary coming up, we can rethink these functions

[glwagner]

I'm closing this issue because I'm judging that it's not of current, timely relevance to Oceananigans development. If you would like to make it a higher priority or if you think the issue was closed in error please feel free to re-open.