Difference between revisions of "ET Workshop Fall 2011 RAD"

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Possibilities
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==Possibilities==
 +
* Leakage scheme
 +
** very ad-hoc
 +
** only mimicks loss due to radiation
 
* Diffusion equation
 
* Diffusion equation
 
** accurate only when mean free path is really short
 
** accurate only when mean free path is really short
 
** almost always implicit to avoid strong CFL limit
 
** almost always implicit to avoid strong CFL limit
 +
** cheap, usually inaccurate
 +
* Flux limited diffusion
 +
** Diffusion + "trick" at lower optical depths
 +
** also simple, and has been used for supernovae simulations
 +
** unclear if working in GR
 +
** limits radiation speed: ad-hoc
 +
** also not very accurate
 +
* Two-Moment-Scheme / Truncated moment scheme
 +
** start with Boltzmann equation
 +
** decompose into moments
 +
** truncate series
 +
** close using some prescription (approximate the rest of the series)
 +
* Full Transport equation
 +
** Full discretization of Boltzmann equation
 +
** extremely complex
 +
** used, e.g., in reactor simulations
 +
** SN/PN discretize equation in different way
 +
** SN not scaling well
 +
** PN might work better
 +
* Monte-Carlo
 +
** no equations, direct simulations
 +
** very simple to implement complicated processes
 +
** more expensive
 +
** given enough computational power, very accurate
 +
** in 3D competitive with other methods in terms of computational needs
 +
 +
==Implementations in "GR"==
 +
* Shibata et al.
 +
** Leakage
 +
** Truncated Moment Formalism
 +
* Shapiro et al.
 +
** Diffusion approximation, grey, 3D
 +
* Garching
 +
** Full Boltzmann transport
 +
** 1D, ray-by-ray
 +
* Caltech / Cactus
 +
** Leakage scheme
 +
** Monte-Carlo
 +
*** 1D only
 +
* AEI
 +
** Leakage

Latest revision as of 16:31, 2 November 2011

Possibilities

  • Leakage scheme
    • very ad-hoc
    • only mimicks loss due to radiation
  • Diffusion equation
    • accurate only when mean free path is really short
    • almost always implicit to avoid strong CFL limit
    • cheap, usually inaccurate
  • Flux limited diffusion
    • Diffusion + "trick" at lower optical depths
    • also simple, and has been used for supernovae simulations
    • unclear if working in GR
    • limits radiation speed: ad-hoc
    • also not very accurate
  • Two-Moment-Scheme / Truncated moment scheme
    • start with Boltzmann equation
    • decompose into moments
    • truncate series
    • close using some prescription (approximate the rest of the series)
  • Full Transport equation
    • Full discretization of Boltzmann equation
    • extremely complex
    • used, e.g., in reactor simulations
    • SN/PN discretize equation in different way
    • SN not scaling well
    • PN might work better
  • Monte-Carlo
    • no equations, direct simulations
    • very simple to implement complicated processes
    • more expensive
    • given enough computational power, very accurate
    • in 3D competitive with other methods in terms of computational needs

Implementations in "GR"

  • Shibata et al.
    • Leakage
    • Truncated Moment Formalism
  • Shapiro et al.
    • Diffusion approximation, grey, 3D
  • Garching
    • Full Boltzmann transport
    • 1D, ray-by-ray
  • Caltech / Cactus
    • Leakage scheme
    • Monte-Carlo
      • 1D only
  • AEI
    • Leakage
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