12.13.2 Including Turbulence Generation Due to Buoyancy

If you specify a non-zero gravity force (in the Operating Conditions dialog box), and you are modeling a non-isothermal flow, the generation of turbulent kinetic energy due to buoyancy ( $G_b$ in this equation in the separate Theory Guide) is, by default, always included in the $k$ equation. However, ANSYS FLUENT does not, by default, include the buoyancy effects on $\epsilon$.

To include the buoyancy effects on $\epsilon$, you must turn on the Full Buoyancy Effects option under Options in the Viscous Model dialog box.

This option is available for all three $k$- $\epsilon$ models and for the RSM.