[Mesa-users] Implementation of the Canuto-Mazzitelli Model

[Vishal Vetrivel]

Hello all,
I have been attempting to implement the Canuto-Mazzitelli and
Canuto-Goldman-Mazzitelli model into MESA for the past few months. I
managed to find an old MESA user list thread from Dr. Warrick Ball (
https://sourceforge.net/p/mesa/mailman/message/33552129/) detailing a
similar implementation. However, since this was a while ago a lot of
the code has since changed. I initially hoped to implement it in the same
way by using a `run_stars_extra.f90` file. However, a bug in the MESA
prevented me from doing so as the routine get_gradT does not call the
custom mlt hook. Instead I have been implementing this into a local copy of
the MESA source code (I am very grateful that you can run multiple versions
of MESA so easily).

In this process I have managed to implement all the modifications made in
the original thread. However, I am facing some issues figuring out where to
implement the turbulent pressure. I have managed to replace the convective
velocity with what I believe should be the equivalent expressions for CM
and CGM. I have not yet implemented setting the mixing length to the
distance to the convective surface yet (I believe there is already an
option to limit the mixing length to the depth so this might not be
necessary). A major issue I had was I am not sure how the new auto_diff
variables are supposed to work so I have manually assigned the derivatives
using the old reference implementation. This is a pretty bad way to do it
so I'd be grateful if anyone could help me with how these variables are
meant to be used.

I have attached my modified mlt.f90 file from the turb module which I
believe should be most if not all the modifications I have made to source
code. I am using version 24.08.1 of MESA. Thank you in advance for your
help.


-- 
Regards
Vishal Sai Vetrivel
5th Year Integrated Masters
School of Physical Sciences
UM DAE CEBS, Mumbai
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20251116/1aa77c55/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: mlt.f90
Type: text/x-fortran
Size: 19464 bytes
Desc: not available
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20251116/1aa77c55/attachment.bin>