Difference between revisions of "ET Workshop Fall 2011 RAD"

From Einstein Toolkit Documentation
Jump to: navigation, search
Line 1: Line 1:
 
Possibilities
 
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
Line 10: Line 13:
 
** limits radiation speed: ad-hoc
 
** limits radiation speed: ad-hoc
 
** also not very accurate
 
** also not very accurate
 +
* Two-Moment-Scheme / Truncated moment
 +
** Start with Boltzmann equation
 +
** Decompose into moments
 +
** Truncate series
 +
** close using some prescription

Revision as of 15:49, 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
    • Start with Boltzmann equation
    • Decompose into moments
    • Truncate series
    • close using some prescription