Changes between Version 7 and Version 8 of u/EricasLibrary


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Timestamp:
09/06/11 15:22:27 (13 years ago)
Author:
Erica Kaminski
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  • u/EricasLibrary

    v7 v8  
     1[[CollapsibleStart(Fedderath, et al. (‘10))]]
     2
     3[http://adsabs.harvard.edu/abs/2010ApJ...713..269F Modeling Collapse and Accretion in Turbulent Gas Clouds: Implementation and Comparison of Sink Particles in AMR and SPH]
     4
     5=== Background ===
     6
     7The numerical difficulty with modeling the collapse of a clump, while keeping track of the entire cloud, is given by the fact that the free-fall time, Tff, where
     8
     9{{{#!latex
     10$ Tff = (3\pi / 32G\rho)^{1/2} $
     11}}}
     12
     13decreases with increasing density and so resolution of the subgrids is demanded over many dynamical time scales. The two methods thus far designed to deal with this matter are 'Jeans heating' and 'sink particles'. Sink particles are a more realistic methodology and was first developed for SPH by Bate et al. ('95). The algorithm was later adapted by Krumholz et al. ('04) for Eulerian AMR. This paper describes a more rigorous series of checks for sink formation.
     14
     15=== Sink Implentation ===
     16
     17Sink particles enable the star formation rate/star formation efficiency, and mass distribution, to be addressed in a robust and quantitative way.
     18
     19Sink algorithms originated from the notion of a density threshold. In earlier work, such a threshold was defined, and once surpassed, a sink particle was placed in the grid.
     20
     21The present work, however, have added in addition to this criterion, a series of checks to insure that sinks are formed only in gravitationally bound and collapsing structures. These are listed as follows:
     22
     23* Converging flow
     24* Bound system
     25* Jean's unstable
     26* Gravitational potential minima
     27
     28Else, under conditions such as shear, a sink may erroneously form.
     29
     30
    131[[CollapsibleStart(Truelove, Klein, Mc Kee, et al. (‘98))]]
    232