T7: Supernova explosion:
Simulating a blast wave

Before the tutorials:

Think about:

• What happens when a star explode?

During the tutorials:

You can run the experiments of a blast wave (as discussed in the lecture).

A simple blast wave

• Create a box with uniform distribution of particles (say 100x100x100).
• Assume low pressure and zero velocities.
• Give a handful of particles in the central part a very large pressure.
• When compiling the code, do not forget to switch off LONG_X, LONG_Y and LONG_Z as you now deal with a cubic volume.

Now we can perform the simulation and analyze it.

• When compiling the code, do not forget to switch on SPH_BND_PARTICLES.
• Try to explain what is happening in the simulation.
• Try to have a look at the temperature of the gas.

Solutions

A simple blast wave

• Again, extending the setup script from T06, combining with what we did in T03, we first create a 100x100x100 cube and then dump enormous energy in the center.
  • setup_blast.pro in IDL
• Example for the simulation
  
  • Examples for Config.sh and blast.param to be used.
  • show_blast.pro in IDL
    you should be able to obtain an animation like this and identify all the phenomena discussed in the lectures
    
• Example using Fortran and gnuplot:
  • ifort -g -traceback -check all -fpe0 -o blastsetup blastsetup.f90
    (this uses glass.txt from T04)
  • ./blastsetup
  • gnuplot grid2.plt (to check that the particle positions are set up correctly)
  • compile Gadget with PERIODIC and NOGRAVITY and without LONG_X, LONG_Y, and LONG_Z.
  • run Gadget using blast.ic as the initial conditions file and output as the snapshot file base in the parameter file, and BoxSize = 2
    (and TimeMax = 10, TimeBetSnapshot = 0.1, and ArtBulkViscConst = 1.5)
  • ifort -g -traceback -check all -fpe0 -o readsnap readsnap.f90
  • for file in output_???; do ./readsnap $file >$file.txt; done
  • gnuplot blast.plt
    (this requires ffmpeg, which is installed on our ltsp machines)
  • xine -l blast.mp4