[FLASH-USERS] energy inaccuracy in Sedov simulation

[Marissa Adams]

Hi Jonathan,

I have also noticed this problem.

The energy one sees in the .dat file is typically less than the input
energy for sim_expEnergy. Also noticed that this is geometry dependent.

I input on the order of 1e10 ergs, and in cartesian I get out 9.2e9; for
cylindrical I get even less! 3.2e8... which is huge. Note I am going based
off of memory here. I cannot get into my HPC system now.

If I am remembering things correctly: seems that in the source code's
volume function in Simulation_init.f90 doesn't always choose the volume
you're choosing to distribute the energy over.

I think it is the section where you'll find a comment that notes the code
will calculate the initial volume and interior pressure. It is assuming pi
r^2 for to get the energy density... where as you may want something
different for other chosen geometries.

If I remember correctly the output energy also changes depending where you
put the hotspot.

Sorry for the haphazard e-mail, but I am experiencing similar issues!

Best,
Marissa




On Tue, Jul 26, 2016 at 10:30 AM, Slavin, Jonathan <jslavin at cfa.harvard.edu>
wrote:

> Hi all,
>
> I've been running supernova remnant evolution simulations.  The
> initialization is done with code taken from the supplied Sedov simulation
> with certain small changes.  One issue that I've run into is that the total
> energy is not very accurate.  That is, though the energy is conserved, the
> total energy, initially input as thermal energy, is below that which is
> given in the sim_expEnergy parameter by ~5%.  Has anyone else run into
> this?  I don't think that it has to do with any of the changes that I've
> made to Simulation_initBlock or Simulation_init.  I'm wondering if
> increasing the sim_nsubzones parameter might help.  Any advice would be
> appreciated.
>
> Thanks,
> Jon
>
> --
> ________________________________________________________
> Jonathan D. Slavin                 Harvard-Smithsonian CfA
> jslavin at cfa.harvard.edu       60 Garden Street, MS 83
> phone: (617) 496-7981       Cambridge, MA 02138-1516
> cell: (781) 363-0035             USA
> ________________________________________________________
>
>


-- 
Marissa Adams                         E-mail: madams at pas.rochester.edu
Graduate Student                      Ph: (585) 402-5779
Department of Physics & Astronomy     Website:
http://www.pas.rochester.edu/~madams/
University of Rochester
478 Bausch & Lomb Hall
P.O. Box 270171
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