[aspect-devel] questions regarding accuracy of no-heat flux boundary condition and help needed for the right entropy viscosity parameters

Timo Heister heister at clemson.edu
Sun Jul 10 06:06:13 PDT 2016

Hey Ying,

I don't have answer to all of your questions, sorry. But:

> The no heat flux boundary conditions are assigned at left and right walls of
> a rectangular box. My first question is that the no heat flux boundary
> condition seems not preserved for both FEM and DG methods after long time
> computation, see attached pdf "T_no_hear_flux_plot.pdf".

What is the size of the heat flux through the left/right and how does
it compare to the top/bottom heat flux? If this is non-zero but
several orders of magnitude smaller, then that is as good as it can
get. If not, then I don't know.

> As shown in the figure 'timeE10.png', the final solutions of FEM(right) and
> DG(left) are very different.

It looks like a problem with a bifurcation, so there could be more
than one valid solution. But I agree that they should probably look
more similar than they currently do.

> Since the test example
> uses constant viscosity, the harmonic average will not help here.

Are you sure? The composition influences the density, which is also
averaged if you turn it on.

Interesting example.


Timo Heister

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