Changes between Version 6 and Version 7 of u/BonnorEbertModule


Ignore:
Timestamp:
10/03/12 16:07:44 (12 years ago)
Author:
Erica Kaminski
Comment:

Legend:

Unmodified
Added
Removed
Modified
  • u/BonnorEbertModule

    v6 v7  
    99and r is the dimensional radius of the sphere, Cs is the isothermal sound speed of the sphere (function of the temperature), and rho_c is the central density of the sphere. Once the user specifies r, rho_c, and xi for the sphere (see next section), astrobear sets both a) the temperature of the sphere using the above equation, and b) the outer density of the sphere. One can then use the ideal EOS in physics.data with a gamma = 1.0001 to approximate the grid as isothermal. Given P = nKT, the pressure of the sphere then drops away from the center of the sphere with the same gradient as rho.
    1010
    11 Now, that all explains the clump object itself, but there is an additional "object" in the BE problem module that controls the ambient medium in which the clump resides. This ambient object is by default set to have a uniform density, equal to the density at the sphere's outer most edge, rho(Rbe). Additionally, it is also in pressure equilibrium with the sphere. That is, Pamb=P(Rbe). Now, since the simulation is isothermal, this condition means the temperature is discontinuous at the sphere-ambient interface, given by P/n = KT, where n is the number-density of the gas.
     11Now, that (^) all explains the clump object itself, but there is an additional "object" in the BE problem module that controls the ambient medium in which the clump resides. This ambient object is by default set to have a uniform density, equal to the density at the sphere's outer most edge, rho(Rbe). Additionally, it is also in pressure equilibrium with the sphere. That is, Pamb=P(Rbe). Now, since the simulation is isothermal, this condition means the temperature is discontinuous at the sphere-ambient interface, given by P/n = KT, where n is the number-density of the gas.
    1212
    1313To summarize, the BE sphere is a clump object that is intialized with the BE density profile. It is placed in an ambient medium object. How to control the different parameters of these objects is described next.