Test Problems: Bondi

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configure.py options

• Must enable
  • --model=HYDRO
  • --gravity
• Must disable
  • --comoving
  • --particle
• Available options
  • Miscellaneous Options

Default setup

• Units

  • External (for Input__TestProb only)

    Unit	[L]	[Dens]	[Mass]	[Temp]
    Value	kpc	g/cm^3	Msun	keV

  • Internal (for all other input files and internal usage)

    Unit	[L]	[V]	[Dens]	[Time] = [L]/[V]	[Mass] = [Dens]*[L]^3
    Value	kpc	1e3 km/s	5.0e-25 g/cm^3	~ 0.978 Myr ~ 1.0 Myr	~ 7.4e6 Msun

• Gravity dt is disabled by setting DT__GRAVITY to arbitrarily large

• MIN_PRES=1.0e-16

Note

• Dual-energy formalism is important for evolving pressure accurately in the high Mach number region (e.g., when Mach number is greater than ~10).
  • Especially important for small GAMMA and large MAX_LEVEL
• The gnuplot script plot_diagonal.gpt plots the simulation results along the diagonal and compare to the analytical solutions. The script plot_profile.gpt plots the shell-average profiles generated by gamer_extract_profile.
• By default it runs only for 10 Bondi time. One may need to run for a longer time in order to get the velocity field converge to the analytical solution at larger radii.
• The contents of the file Input__Flag_User are not used actually.
• For large MAX_LEVEL (e.g., 11), using OPT__DT_LEVEL=3 for the first step may result in unphysical results since the time-step would likely be over-estimated due to both the zero initial velocity and the disabling of DT__GRAVITY.
  • It's better to adopt OPT__DT_LEVEL=2 and small DT__FLUID_INIT for the first step, dump data, and then restart with OPT__DT_LEVEL=3.

Links

Main page of Test Problems