# Including Rotation

This section discusses how to include the effects of rotation in GYRE calculations. Further details of GYRE’s treatment of rotation are presented in the Oscillation Equations and Tidal Equations chapters.

## Setting the Rotation Rate

There are two different ways to define the rotation angular velocity $$\Omega$$, via parameters in the &rot namelist group.

• If Omega_rot_source = MODEL, then differential rotation is assumed with a spatially varying $$\Omega$$ obtained from the stellar model. If the model doesn’t have this capability (see the Model Capabilities section), then $$\Omega$$ is set to zero throughout the star.

• If Omega_rot_source = UNIFORM, then uniform rotation is assumed with a spatially constant $$\Omega$$ set by the Omega_rot and Omega_rot_units parameters.

## Enabling Doppler Effects

Doppler effects are enabled by default whenever calculations are performed with non-zero $$\Omega$$ and mode azimuthal order $$m$$. To disable these effects, set m= 0 in the &mode namelist group.

## Enabling Coriolis Effects

Coriolis effects are disabled by default, but can be enabled using the traditional approximation of rotation (TAR) by setting coriolis_method='TAR' in the &rot namelist group. The solution family is controlled by the rossby parameter of the &rot namelist group; set to .TRUE. for the Rossby family, and to .FALSE. (the default) for the gravito-acoustic family.