[FLASH-BUGS] Issue with shocks crossing refinement boundaries

[Mike Zingale]

The problem appear to be the internal enery evolution.  By default, when
the kinetic energy dominates over the internal energy, an internal energy
evolution equation is solved, but this equation is not in conservative
form.  Try running your test problem with eint_switch = 0.0, and the
energy should be conserved very well.  For most flows, the default
eint_switch = 1.e-4 seemed to do a good job.  I'll play around with this
some more.

Mike

On Wed, 14 Aug 2002, Colin McNally wrote:

> Hi,
>             I have produced a setup which for me appears to cause some 
> rather severe energy conservation issues in FLASH. What I have done is 
> modify the standard Sedov test problem to simulate a run with a 
> mass-based refinement criteria. The central region of the box is fixed 
> to refinement level 5 and the exterior is fixed to refinement level 4. 
> The problem appears to evolve correctly until thew shock hits the 
> refinement boundary.  At this point the solution goes all wacky. A 
> reflecting from the boundary of some sort ought to be expected, as FLASH 
> doesn't seem to have anything in its prolong and refine operators to 
> dampen this. A reflected wave is quite apparent in the solution. 
> However, inspection of the outputted flash.dat file also shows 
> significant energy loss.
> 
>   I have included a tarball with the flash.dat file from my run and the 
> problem directory. I have reproduced this problem on a tru64/Compaq 
> Fortran Alpha cluster with my own patched version of FLASH and a clean 
> copy of FLASH2.1 on a Linux/Intel Fortran Intel box. The problem is run 
> in 2D The differences from the original distributed Sedov test are as 
> follows:
>     - central 1/8th of box is fixed at refinement level 5
>     - remainder of box at refinement level 4
>     - larger box size (2 by 2 instead of 1 by 1)
>     - longer run (to  t=0.4)
> The setup command used was:
> ./setup sedovref -auto -2d
> 
>   I have observed that this issue does not appear when using truncation 
> level refinement criteria. Also, the reflected wave is expected when 
> using this forced refinement. However, non-conservation in a 
> conservative hydro scheme is worrying. Similar situations where shocks 
> must cross refinement boundaries will occur in astrophysical problems 
> were refinement must be determined by a mass criteria(ex: cosmology 
> problems).
> 
> Thanks,
> 
> Colin McNally
> McMaster University
> 
>