The Gravity global feature is automatically added when Include gravity is selected at the interface level in the Physical Model settings. It defines the gravity forces from the Acceleration of gravity value.

The Acceleration of gravity (SI unit m/s, default value −gconstez in 2D axial symmetry and 3D and −gconstey in 2D) is used to define the gravity forces. It should be a global quantity.

When in addition to Include gravity also Rotating frame is selected (only possible in 3D and 2D axial symmetry), the Project gravity vector on rotation axis checkbox is available (by default selected).