[Mesa-users] Noisy Brunt–Väisälä frequency

[Francis Timmes]

i can't tell if you are showing N^2 as calculated by mesa or 
if you are calculating N^2 on your own from the mesa profiles.

if the latter, then be aware of the subtleties (or no so subtle!) described
in section 3.3 of mesa II, paxton et al 2013. as an alternative
you may want to consider adding brunt as calculated by mesa 
to the profiles (see $MESA_DIR/star/defaults/profile_columns.list)
and as rich mentioned, consider adjusting the set of controls in 
http://mesa.sourceforge.net/controls_defaults.html#Brunt_controls .

fxt



> On Aug 30, 2018, at 2:11 PM, Pedro Nuno David Gomes via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Dear MESA users,
> 
> I'm trying to calculate the square of Brunt–Väisälä frequency, N^2, for different life stages of a star with 1.5M_sun. However, the result is very noisy, and spiky. Besides this, I noticed that near the center N^2 assumes negative (although very small) values.
> 
> How can I solve this?
> 
> I attach two figures that show the behavior I mentioned, and below I send my inlist.
> 
> Thank you for your help,
> 
> Pedro
> 
> ------------------------------------------------------------
> 
> &star_job
> 
> 	change_lnPgas_flag = .true.
>        new_lnPgas_flag = .true.
>        pgstar_flag = .true.
> 
> 	save_model_when_terminate = .true.
> 	save_model_filename = 'final.mod'
> 
> 	set_initial_age = .true.
> 	initial_age = 0
> 
> / !end of star_job namelist
> 
> &controls
> 
> 	initial_mass = 1.5
> 	initial_z = 0.02
> 	use_Type2_opacities = .true.
> 	Zbase = 0.02
> 
>        calculate_Brunt_N2 = .true.
> 
> 	overshoot_f_below_nonburn_shell = 0.023
> 	overshoot_f_above_burn_h_shell = 0.023
> 	overshoot_f_above_burn_he_core = 0.023
> 
> 	overshoot_f0_below_nonburn_shell = 0.005
> 	overshoot_f0_above_burn_h_shell = 0.005
> 	overshoot_f0_above_burn_he_core = 0.005
> 
> 	photo_interval = 50
> 	profile_interval = 50
> 	history_interval = 1
> 	terminal_interval = 10
> 	write_header_frequency = 10
> 
> 	mesh_delta_coeff = 0.8
> 
>        log_Teff_lower_limit = 3.71 ! (stop here)
> 
> 
> / ! end of controls namelist
> 
> &pgstar
> 
> / ! end of pgstar namelist
> <brunt_1.png><brunt_2.png>_______________________________________________
> mesa-users at lists.mesastar.org
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>