[Mesa-users] Questions about MLT++ and center variables

[Francis Timmes]

hi matheus,


> On Aug 27, 2018, at 8:03 AM, Matheus Bernini via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hello MESA users,
> 
> I'm an undergraduate student and I'm using MESA to study the evoltion of massive stars up to the oxigen burning.
> 
> 1) On MESA's second paper (section 7.3.1) it's shown different results depending if one choose MLT or MESA's MLT++. Which result should I prefer as 'the most correct'?

mlt and mlt++ are 1d approximations to 3d turbulence.
in this sense they are both wrong. in most regimes within
a star the two will yield the same result, nearer the
surface mlt++ allows a more efficient transport of energy.
which is more "correct", if any, is up to a user to decide.

> 2) How can I switch between MLT and MLT++ on my MESA models?


http://mesa.sourceforge.net/controls_defaults.html#okay_to_reduce_gradT_excess
okay_to_reduce_gradT_excess = .true. activates "mlt++".


> 
> 3) How the center variables (T_c, rho_c,etc) are defined, in the most central cell or  as a region composed by a given amount of cells near the center?

http://mesa.sourceforge.net/controls_defaults.html#center_avg_value_dq


fxt


> 
> Cheers
> 
> ------------------------------------------------------
> Matheus Bernini Peron
> Undergraduate student
> Observatório do Valongo,
> Federal University of Rio de Janeiro
> ------------------------------------------------------
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