Poiseuille flow 3d setup

[svchb]

Extracted from #922

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.98%. Comparing base (ca35699) to head (bb3f043).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1075      +/-   ##
==========================================
+ Coverage   88.81%   88.98%   +0.16%     
==========================================
  Files         128      128              
  Lines        9828     9828              
==========================================
+ Hits         8729     8745      +16     
+ Misses       1099     1083      -16     

Flag	Coverage Δ
total	88.98% <ø> (+0.16%)	⬆️
unit	67.03% <ø> (ø)

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[efaulhaber]

I guess @LasNikas should take a look here, since you copied his code.

[LasNikas]

That works for me. However, it might be worth mentioning in the 2D and 3D examples that the pressure gradient is defined over the entire inflow-to-outflow extent and that the boundary zones free surfaces start and end at x=0 and x=L, respectively.
This means that the boundary zones are effectively part of the computational domain.
Otherwise, this could cause confusion during the validation process.

[svchb]

That works for me. However, it might be worth mentioning in the 2D and 3D examples that the pressure gradient is defined over the entire inflow-to-outflow extent and that the boundary zones free surfaces start and end at x=0 and x=L, respectively.
This means that the boundary zones are effectively part of the computational domain.
Otherwise, this could cause confusion during the validation process.

I have added a comment to the setups

[svchb]

/run-gpu-tests

[svchb]

/run-gpu-tests