[mesa-users] Change Mesh Resolution Dynamically?

[Bill Paxton]

Hi,

There are controls that let you increase the resolution adjacent to a convection zone boundary.
You specify the type of convection zone (non-burn, h-burn, he-burn, other),
the boundary (upper or lower), 
and the direction relative to the boundary (above or below).
You give the extent of the increased resolution in terms of the local pressure scale height.

e.g.	for below lower nonburn convective boundary
      xtra_coef_b_l_nb_czb = 1   ! Value < 1 gives increased resolution.
      xtra_dist_b_l_nb_czb = 0.2 ! distance in units of pressure scale height

You should of course read through the entire list of controls for the mesh resolution in star/defaults/controls.defaults.

Good luck,
Bill



On Sep 8, 2014, at 4:52 PM, Spencer C Wallace wrote:

> Hello,
> 
> I have added some code to the 'other_mixing' routine that mixes material at the convective boundary according to a 1D entrainment law. At each time step, I calculate some deltaM according to how much material should be entrained and crank up the diffusion coefficient in all zones that fall within deltaM of the convective boundary.
> 
> In the types of models I am working with, this deltaM often only covers one or two extra zones. This introduces some noise, as the difference between mixing one and two extra zones can be quite dramatic.
> 
> Now the most obvious solution is to increase the mesh resolution, which does fix the problem. I understand that I can do this by changing the inlist parameters, but that requires some trial and error, as there no way to know how many zones the entrainment will cover at each time step until you actually run the model.
> 
> I was wondering how I could make the mesh resolution scale with the entrainment strength. My 'other_mixing' routine calculates a deltaM at each time step, which is then translated into some number of zones, deltaN. If deltaN is too small, is there some way I can temporarily bump up the mesh resolution?
> 
> I saw that there is an 'other_mesh' hook that I can add code to, but I didn't see any variables in 'star_data.inc' that looked like they would allow me to tweak the mesh resolution. Any suggestions?
> 
> Spencer Wallace
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