[FLASH-USERS] 2D Spherical and Cartesian Geometry
Carlo Graziani
carlo at oddjob.uchicago.edu
Fri Sep 23 10:25:21 EDT 2016
On 09/23/2016 09:16 AM, Michiel Bustraan wrote:
> Secondly, I did read the section in the userguide on geometries, and I understand that different geometries handle block volumes differently.
> But even so, shouldn't it be possible to simulate a 2D slice of a spherical shock using Cartesian geometry (say, a 2D simulation of the equator)?
> Or does the nature of the Cartesian geometry make it fundamentally inappropriate for this kind of simulation?
>
The nature of the Cartesian geometry make it fundamentally inappropriate
for this kind of simulation.
2-d simulations assume a symmetry, and assign the "direction" of the
symmetry along the y axis. There are two available symmetries: planar
symmetry (d/dy=0) and azimuthal symmetry (d/dphi=0). In the first case,
the y axis represents invariant translation, in the second the y axis
represents invariant rotation about the z-axis.
You select the first case by specifying "Cartesian", the second by
specifying "Spherical". The geometry selection selects symmetry, as
well as block structure.
So, you see, as Mordecai noted, you can only produce an exploding line
charge in cartesian geometry. If you want a spherically-symmetric point
explosion in 2d, your only option is spherical.
Carlo
--
Carlo Graziani (773) 702-7973 (Voice)
University of Chicago Flash Center (773) 702-6645 (FAX)
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carlo at oddjob.uchicago.edu | --- Kin Hubbard
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