### 12.6.3. Appendix 2: Summary of Numerics Settings With ANSYS CFX

| Unsteady Simulation | Comment
--- | --- | ---

Convection Terms

CD / BCD

CD on simple geometries (also inside LES regions). In case of wiggles in solution use BCD

The default scheme for SBES and SAS is a hybrid scheme that switches automatically between High Res and CD. Recent experience indicates that BCD is generally easier to apply and often yields the same accuracy.

CDS Bound enables shifting between the classical BCD scheme and the Central Difference scheme.

Time discretization | Second order backward Euler | Use CFL<1 in LES zones if possible. This condition can also be relaxed depending on the flow. Bounded for second order turbulence quantities is default (, , ) and other positive quantities (volume fraction, and so on).

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