Test Problems: JeansInstability

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configure.py options

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

Default setup

• Resolution = 64^3
• Simulation time
  • stable -> one period
  • unstable -> grow/decay by a factor of 50
• Gravitational constant = 1/(4*pi) = 0.07957747154

Note

• Support both hydro and MHD. For the latter, a fast-wave solution is adopted.
• Support both 1D and 3D cases.
  • set by Jeans_Dir
• A simple gnuplot script plot.gpt is attached.
• Record__L1Err records the L1 errors.
• Jeans_* record the numerical and analytical solutions along the diagonal.
• Example parameters

  • Stable right-moving wave

    Jeans_Rho0        1.0            # background density
    Jeans_Rho1        1.0e-6         # density perturbation amplitude
    Jeans_P0          1.0e-2         # background pressure
    Jeans_v0          0.0            # background velocity [0.0]
    Jeans_B0          1.0e-2         # background magnetic field amplitude
    Jeans_Sign       +1.0            # (>0/<0) --> (stable:right/left-moving wave; unstable:growing/decaying mode) [+1]
    

  • Unstable growing mode

    Jeans_Rho0        2.0            # background density
    Jeans_Rho1        1.0e-6         # density perturbation amplitude
    Jeans_P0          1.0e-2         # background pressure
    Jeans_v0          0.0            # background velocity [0.0]
    Jeans_B0          1.0e-2         # background magnetic field amplitude
    Jeans_Sign       +1.0            # (>0/<0) --> (stable:right/left-moving wave; unstable:growing/decaying mode) [+1]
    

Links

Main page of Test Problems