# 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.