[Mesa-users] Setting the value of omega/omega_critical

[AVG]

Dear all,

I am trying to simulate a rotating star with a given value of its 
omega/omega_critical, but I find that this parameter varies strongly in 
the first 20 Myears of the simulation since the ZAMS starts (I am 
specially interesed on what happens in those first 20 Myears after the 
ZAMS, as the work I am doing is focused on some previous results 
obtained until that time).

In my simulations I turn on the rotation at the begining of ZAMS, and 
shortly after it starts the value of its omega changes quickly, as we 
can see in the image I attach. I want to set the value of the omega 
along the simulation, as I need to analyse results obtained with GYRE 
for some specific omegas (so the increasing behaviour of the omega makes 
it really difficult for me).

I also attach the inlist I have used.

Could someone give me some tips on this?  Any help will be appreciated.

Best regards,

Antonio Varo
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! inlist to evolve a 15 solar mass star

! For the sake of future readers of this file (yourself included),
! ONLY include the controls you are actually using.  DO NOT include
! all of the other controls that simply have their default values.

&star_job
  ! see star/defaults/star_job.defaults  
  ! begin with a pre-main sequence model
    create_pre_main_sequence_model = .true.

  ! save a model at the end of the run
    save_model_when_terminate = .false.
    save_model_filename = '15M_at_TAMS.mod'

  ! display on-screen plots
    pgstar_flag = .false.
    
  ! My options
  ! to include rotation in the model
    new_rotation_flag = .true.
    change_rotation_flag = .false.
    change_initial_rotation_flag = .false.

  ! Accounts for surface rotational velocity (in Km/s)
  !  new_surface_rotation_v = 65
  !  set_surface_rotation_v = .true.
  !  set_initial_surface_rotation_v = .false.

  ! Or in units of Omega_critical (DEFAULT)
    new_omega_div_omega_crit = 0.5
    set_omega_div_omega_crit = .true.
    set_initial_omega_div_omega_crit = .true.
  !  set_omega_div_omega_crit_step_limit = -1

  ! The following apply when rotation is off and model satisfies the "near zams" test. Each turns on rotation and sets step limit. Only applies if > 0

    set_near_zams_omega_div_omega_crit_steps = +1
    set_near_zams_surface_rotation_v_steps = 1

  ! The following are for settle in the new rotation (DEFAULT)

    num_steps_to_relax_rotation = 100
    relax_omega_max_yrs_dt = 1d4
   
    relax_omega_div_omega_crit = .false.
    relax_initial_omega_div_omega_crit = .false.
    near_zams_relax_omega_div_omega_crit = .false.

    relax_surface_rotation_v = .false.
    relax_initial_surface_rotation_v = .false.
    near_zams_relax_initial_surface_rotation_v = .true.

  ! To include diffusion of angular momentum

    new_D_omega_flag = .false.
    change_D_omega_flag = .false.
    change_initial_D_omega_flag = .false.

    new_am_nu_rot_flag = .false.
    change_am_nu_rot_flag = .false.
    change_initial_am_nu_rot_flag = .false.
    use_D_omega_for_am_nu_rot = .true. 
    
    
    
/ ! end of star_job namelist


&eos
  ! eos options
  ! see eos/defaults/eos.defaults

/ ! end of eos namelist


&kap
  ! kap options
  ! see kap/defaults/kap.defaults
  use_Type2_opacities = .true.
  Zbase = 0.02

/ ! end of kap namelist


&controls
  ! see star/defaults/controls.defaults
  ! starting specifications
    initial_mass = 2.9 ! in Msun units
    initial_z = 0.02

  ! options for energy conservation (see MESA V, Section 3)
  !   use_dedt_form_of_energy_eqn = .true.
  !   use_gold_tolerances = .true.

  ! stop when the star nears ZAMS (Lnuc/L > 0.99)
  !  Lnuc_div_L_zams_limit = 0.99d0
  !  stop_near_zams = .true.

  ! stop when the center mass fraction of h1 drops below this limit
    xa_central_lower_limit_species(1) = 'h1'
    xa_central_lower_limit(1) = 1d-3
    
  ! stop when total power from reactions burning helium (in Lsun units) is > this.
  !  power_he_burn_upper_limit = 1d3
  min_overshoot_q = 0.2
  max_age = 2d7
  write_pulse_data_with_profile = .true.
  profile_interval = 25
  pulse_data_format = 'GYRE'
  
/ ! end of controls namelist