Runtime Parameters Documentation for FLASH Release 4-beta


physics/Gravity
    useGravity [BOOLEAN] [FALSE]
        Whether gravity calculations should be performed.

physics/Gravity/GravityMain
    useGravity [BOOLEAN] [TRUE]
        Should the gravity calculations be performed?

physics/Gravity/GravityMain/Constant
    gconst [REAL] [-981.]
        Valid Values: Unconstrained
        Gravitational acceleration constant
    gdirec [STRING] ["x"]
        Valid Values: Unconstrained
        Direction of acceleration ("x", "y", "z")

physics/Gravity/GravityMain/PlanePar
    gravsoft [REAL] [.0001]
        Valid Values: Unconstrained
        softening length
    ptdirn [INTEGER] [1]
        Valid Values: Unconstrained
        x = 1, y = 2, z = 3
    ptmass [REAL] [10000.]
        Valid Values: Unconstrained
        mass of the point
    ptxpos [REAL] [1.]
        Valid Values: Unconstrained
        location of the point mass, in the ptdirn direction

physics/Gravity/GravityMain/PointMass
    gravsoft [REAL] [0.001]
        Valid Values: Unconstrained

    ptmass [REAL] [10000.]
        Valid Values: Unconstrained

    ptxpos [REAL] [1.]
        Valid Values: Unconstrained

    ptypos [REAL] [-10.]
        Valid Values: Unconstrained

    ptzpos [REAL] [0.]
        Valid Values: Unconstrained


physics/Gravity/GravityMain/Poisson
    grav_temporal_extrp [BOOLEAN] [FALSE]
        extrapolate or otherwise rescale
    grav_unjunkPden [BOOLEAN] [TRUE]
        controls whether Gravity_potentialListOfBlocks attempts to restore the
        part of the "pden" ("particle density") UNK variable that is due to
        particles, or leaves "pden" as it is, after a Poisson equation solve.
        This only applies meaningfully when a "pden" variable is declared and
        the gravitational potential is calculated by solving a Poisson equation
        whose right-hand side includes a mass distribution to which both
        hydrodynamic fluid density and massive particles contribute. The "pden"
        variable will have been set to the sum of the fluid density ("dens"
        variable) and the density resulting from mapping massive particles to
        the mesh, so that is what remains in "pden" when grav_unjunkPden is set
        to FALSE. Otherwise, "dens" will be subtraced from "pden" before
        Gravity_potentialListOfBlocks returns, and "pden" will be left
        containing only the mass density that is due to particles.
    point_mass [REAL] [0.e0]
        Valid Values: Unconstrained
        mass of the central point-like object
    point_mass_rsoft [REAL] [0.e0]
        Valid Values: Unconstrained
        softening radius for the point-like mass (in units of number of the
        finest level cells)
    updateGravity [BOOLEAN] [TRUE]
        allow gravity value to be updated