[aspect-devel] Cylindrical coordinates

[Wolfgang Bangerth]

> Cylindrical coordinates has been on my radar for a while, but I'm
> probably not going to pursue it right now. I'm trying to wrap up this
> whole dissertation thing, and need to weigh the time commitment of
> adding this feature vs. time to just run the models in 3D. Seems like 3D
> Cartesian wins again. As always, XKCD sums up my predicament well:
> https://xkcd.com/974/

:-)


>> My understanding is that in 2D, the spherical shell model is equivalent
>> to a 2D annulus.

Correct. It corresponds to a horizontal slice through an infinity cylinder 
whose central region you have excluded (i.e., a cross section through the 
metal part of a pipe).


>> I was suggesting the spherical annulus, which is actually a three
>> dimensional equatorial slice with a very small latitudinal opening
>> angle. This is like taking a (thin) slice of pizza, tipping it sideways,
>> and making a volume of revolution :). In this geometry the area ratios
>> of the surface and CMB are preserved.

So you expect a latitudinal variation but not a variation in angular direction 
and consequently want to simulate in the r/theta plane but ignore phi? Or do I 
misunderstand and you really want to simulate in the r/theta plane and say 
that the variation in phi is so small that there is no variation?

Best
  W.


-- 
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Wolfgang Bangerth          email:                 bangerth at colostate.edu
                            www: http://www.math.colostate.edu/~bangerth/