[yt-users] integrated quantities in cylindrical

[Roman Yurchak]

Hello,

I'm interested in getting some integrated quantities from a cylindrical
2d FLASH simulation.

Just to be sure, I started by comparing the total simulation mass
computed by yt ( with pf.h.all_data().quantities['TotalQuantity'] etc.)
and the one provided in FLASH logs, and the results are rather different
[see attachment]:
  * _Values_:  difference of up 8% between the two methods
  * _Time evolution_: total mass is decreasing in time according to
FLASH (which is ok with open boundary conditions) but it is increasing
with the yt's integration.
  * _Sensitivity to resolution_: there are jumps in total density given
by yt for the time steps where the maximum refinement level is manually
decreased.

Would anyone know what might be the reason for this behaviour?

Just in case, I tried to do a second order integration instead of simply
summing the values in all the cells, but if didn't make an error, the
correction was negligible.

I can provide data and the yt script I'm using by PM if some could look
into this.

Thank you,
Regards,
-- 
Roman Yurchak
-------------- next part --------------
# t            : simulation time
# mass_yt      : total simulation mass integrated with yt roughly as : 
#                   [....]
#                   dd = pf.h.all_data()
#                   res = dd.quantities['TotalQuantity']('CylindricalCellMass')[0]
#                   [...]
# mass_flash   : total simulation mass as given by FLASH
# mass_err_rel : relative error

             t    mass_yt  mass_flash  mass_err_rel
0    0.000E+00  1.329E-03   1.416E-03   937.996E-03
1   25.002E-09  1.367E-03   1.412E-03   968.114E-03
2   50.003E-09  1.400E-03   1.400E-03  1000.000E-03
3   75.010E-09  1.412E-03   1.367E-03     1.033E+00
4  100.013E-09  1.439E-03   1.329E-03     1.083E+00