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 options 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 option.

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 summary.domega_rot and detail.domega_rot output fields). In the latter case, the traditional approximation of rotation (TAR) can be enabled by setting the lambda_method option to 'TAR-GRAVITY' (for gravito-acoustic modes) or to 'TAR-ROSSBY' (for Rossby modes).