Recommended parameters for robustness

When setting up a computation, the following options are recommended for a good robustness.

Default combinations may be more precise, and others even more robust (but more imprecise), but the following are reasonably good "all-around" settings.

Turbulence model

Depends on the computation and modeling requirements, but the most robust options are usually:

• k-ω SST with "all y+" wall law.
• k-ε linear production with 2 scale wall law.

Gradient reconstruction

• Green-Gauss with iterative handling of non-orthogonalities is recommended.
  • If this fails, using a least-squares based gradient with extended neighborhood may be an alternative
  • Green-Gauss based on least-squares face values interpolation behaves similarly to that with iterative handling of non-orthogonalities, and can be made a bit smoother using an extended neighborhood, but have been observed to be less robust on a case with stratification (though it seemed more robust on others)

Other options

• Handling of transposed gradient: off.
• Pseudo-coupled velocity-pressure solver: off.
• Improved pressure interpolation: on (by default starting with v7.0).
• Convective scheme: SOLU (all variables, except for turbulence, which can be upwind).
• Outlet condition: imposed pressure outlet.

For a steady case, use the "steady" (idtvar = 2) time scheme, with maximum CFL of 1.0.

• prior to version 7.0, this was referred to as "local time step" (with a nother scheme named "steady" which has been deprecated).