# Including Rotation

This section discusses how to include the effects of rotation in GYRE calculations. See the Rotation Effects section for further details of GYRE’s rotation treatment.

## Setting the Rotation Rate

There are two different ways to define the rotation angular frequency
\(\Orot\), via parameters in the `&rot`

namelist group.

If

`Omega_rot_source`

=`'MODEL'`

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

`Omega_rot_source`

=`'UNIFORM'`

, then uniform rotation is assumed with a spatially constant \(\Orot\) set by the`Omega_rot`

and`Omega_rot_units`

parameters.

## Incorporating Doppler Effects

The Doppler Shift effect is incorporated automatically
whenever calculations are performed with non-zero \(\Orot\) and
mode azimuthal order \(m\). To disable this effect, set
`m`

= `0`

in the `&mode`

namelist group.

## Incorporating Coriolis Effects

Incorporating the effects of the Coriolis force can be done using a
perturbative treatment or a
non-perturbative treatment. In the former
case the effects are be applied as a post-calculation correction to
non-rotating eigenfrequencies (see the `domega_rot`

output item
in the Summary Files and Detail Files sections). In the
latter case, the traditional approximation of rotation (TAR) can be
enabled by setting `coriolis_method`

=`'TAR'`

in the
`&rot`

namelist group.

The TAR solution family is controlled by the
`rossby`

parameter of the `&rot`

namelist group; set to
`.TRUE.`

for the Rossby family, and to `.FALSE.`

for the
gravito-acoustic family.