Including Rotation

This chapter briefly discusses how to include rotation effects in GYRE calculations. Further details of GYRE’s treatment of rotation are presented in the Rotation Effects section.

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.