[FLASH-USERS] Comet simulation

[clopezsisterna at casleo.gov.ar]

Hello,

We are trying to simulate the interaction between the solar wind and a
comet. We follow the example of Ekenback and Holmstrom (PARA2004,
Dongarra, Madsen and Wasnievski Eds., LNCS 3732, Springer-Verlag, Berlin,
2005, pp.554-562) but these authors used FLASH 2 and we want to use FLASH
4.2.2.

We decide to use the 8-wave MHD implementation because it is the default
in the FLASH user guide examples and we think that it is easy to convert
from FLASH 2. In any case, it must work using the 8-wave or the unsplit
staggered mesh implementations.

The main idea is to include in the simulation a new source due to the
comet and study its interaction with the solar wind. We simulate the solar
wind using a modification of the Wind Tunnel example but without the step.
We simulate the inflow in Simulation_initBlock setting density, velocity,
magnetic field and temperature at the left x-boundary (boundary type
"user") and setting the boundary condition at the right x-boundary as
"outflow". It works without any problem.

Then we included the cometary source simulation the comet plasma
production as a function of the distance to the comet, A(r), including the
source in the MHD equations adding terms to the right side of the
continuity equation (+A(r)) and the momentum equation (-A(r)*v). We test
several places to include the cometary source (hy_8wv_sweep, hy_8wv_source
or Hydro that calls hy_8wv_sweep) but we obtain always the same result and
after few steps we have the following error:

      26 2.3500E-01 5.0000E-03  (-4.922E+00, -2.422E+00,  0.000E+00) |
1.083E-02
      27 2.4500E-01 5.0000E-03  (-4.922E+00, -2.422E+00,  0.000E+00) |
1.083E-02
  iteration, no. not moved =            0         189
  iteration, no. not moved =            1           0
 refined: total leaf blocks =          226
 refined: total blocks =          293
      28 2.5500E-01 5.0000E-03  (-1.172E+00, -3.672E+00,  0.000E+00) |
1.083E-02
[flash_convert_cc_hook] PE=      3, ivar=  3, why=1
 Trying to convert non-zero mass-specific variable to per-volume form, but
dens is zero!
 DRIVER_ABORT: Trying to convert non-zero mass-specific variable to
per-volume form, but dens is zero!
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 3

It seems that the problem is a zero density but this is strange since our
comet source always add a positive quantity to the density. So, we cannot
realize where is the problem in the subroutine of the comet source or
where can we begin to search for debugging.
Thank you,

Cecilia López
Ph-D student
CASLEO