[FLASH-USERS] [EXT] cylindrical vs polar

[Reyes, Adam]

Hi Maksim,

2D cylindrical in FLASH refers to an r-z geometry, whereas polar is an r-phi geometry. In the case of “axisymmetric Sod” since the azimuthal derivatives are zero the r-z cylindrical geometry is the correct choice.

As for the calculation of the artificial viscosity the 2D cylindrical geometric factors are handled with the “hy_geometry .NE. CARTESIAN” case. 

Adam

> On Apr 30, 2021, at 5:46 AM, Maksim Kozlov <maksim.kozlov at nu.edu.kz> wrote:
> 
> Dear Flash users,
> in chapter 34 of users manual there is an example of configuring "axisymmetric variant of the Sod problem". According to the manual such problem should be set up by "./setup Sod -auto -2d -geometry=cylindrical." Which is wrong because in 2D it is called "polar". And it is not just question of terminology. If you look for example at source code "hy_uhd_getFaceFlux.F90" then for 2 dimensional case only spherical and polar geometries are considered when coefficient of viscosity cvisc is calculated. Is this a bug or I do not understand something?
> I would really appreciate if anybody can help me with this issue.
> Thank you very much!
> Maksim Kozlov