Thanks again, Tomek. It now seems to work just fine. I understand that
the rotational symmetry axis is special, and that one possibly wants the
artificial viscosity to scale with cylindrical r. But I still don't
understand why the artificial viscosity should depend on my choice of
domain normalization. For example, why should the artificial viscosity be
different if I choose xmin=0.0 ,xmax=1.0 as opposed to xmin=0.0,
xmax=100.0?
-Sean
On Fri, 26 Sep 2003, Tomasz Plewa wrote:
> On Fri, Sep 26, 2003 at 03:47:23PM -0400, Sean Matt wrote:
> [snip]
>
> > This actually raises the issue of whether the quantity (x(i)**2 -
> > x(i-1)**2) is the right formulation for the calculation of the
> > artificially viscocity. We're not sure why the actual numerical value of
> > the x coordinate should be relevant, since it is arbitrarily set by the
> > user (e.g., 201**2-200**2 does not equal 2**2-1**2). Perhaps what is
> > needed is something like the square of the difference, (x(i) - x(i-1))**2,
> > but since this is a different quantity, this should be looked at with
> > care, and we don't know the correct formulation.
>
> There should be no flow across the symmetry axis at r=0 (the area
> vanishes there). The viscous flux (coefficient) should be set to zero.
>
> Tomek
>
--_______________________________________________________________________ Sean P. Matt CITA National Fellow phone: (905) 525-9140 x 23189 Physics & Astronomy Dept. http://www.physics.mcmaster.ca/~matt McMaster University -----------------------------------------------------------------------
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