Nonlinear iterative projection methods with multigrid in photon frequency for thermal radiative transfer
Abstract
This paper presents nonlinear iterative methods for the fundamental thermal radiative transfer (TRT) model defined by the timedependent multifrequency radiative transfer (RT) equation and the material energy balance (MEB) equation. The iterative methods are based on the nonlinear projection approach and use multiple grids in photon frequency. They are formulated by the highorder RT equation on a given grid in photon frequency and loworder moment equations on a hierarchy of frequency grids. The material temperature is evaluated in the subspace of lowest dimensionality from the MEB equation coupled to the effective grey loworder equations. The algorithms apply various multigrid cycles to visit frequency grids. Numerical results are presented to demonstrate convergence of the multigrid iterative algorithms in TRT problems with large number of photon frequency groups.
 Publication:

Journal of Computational Physics
 Pub Date:
 November 2021
 DOI:
 10.1016/j.jcp.2021.110568
 arXiv:
 arXiv:2011.05427
 Bibcode:
 2021JCoPh.44410568A
 Keywords:

 Thermal radiative transfer;
 Boltzmann equation;
 Highenergy density physics;
 Iteration methods;
 Multigrid methods;
 Variable Eddington factor;
 Mathematics  Numerical Analysis;
 Computer Science  Computational Engineering;
 Finance;
 and Science;
 Physics  Computational Physics
 EPrint:
 21 pages, 6 figures, 2 tables