Radiation

Warning

• MFIX-Exa must be built with RTE enabled which requires hypre.

The following inputs are defined using the prefix radiation:

Key	Description	Type	Default
model	Radiation model. Options: P1 - \(\mathrm{P}_1\) spherical-harmonics approximation. FV - Finite-volume discretization of the radiation transport equation.	String	None
enable_scaling	Enable mean beam-length scaling.	Bool	false
update_int	Solve for the radiation intensity on the interval in time steps. This input cannot be specified with radiation.update_per_approx.	Int	None
update_per_approx	Solve for the radiation intensity on the approximated lapsed time. This input cannot be specified with radiation.update_int.	Int	None
domain.is_black	Override domain radiation boundary conditions with black surfaces: boundary temperature is set to 0 K and emissivity is set to 1. This is an advanced setting and should be used with caution because it makes the radiation boundary conditions differ from the flow boundary conditions.	Ints<3>	0

RTE P₁ solver

The following inputs are defined using the prefix rte.P1:

Key	Description	Type	Default
A1	Legendre coefficient for scattering phase function.	Real
maxConvergeIter	Maximum allowed iterations to get a converged solution.	Int	10
L2_convergence_tol	Convergence threshold on L2 norm of incident radiation (G).	Real	1.0e-5
NOS_correction	Non-orthogonal and skewness correction on face fluxes.	Bool	false
flux_redistribution	Redistribute the flux or not during the non-orthogonal corrections.	Bool	false
LeastSquare_stencil_size	Stencil size for the least square regression.	Int	3

RTE FV solver

The following inputs are defined using the prefix rte.fv:

Key	Description	Type	Default
quadrature_resolution_theta	Number of polar discretizations in each quadrature.	Int	None
quadrature_resolution_phi	Number of azimuthal discretizations in each quadrature.	Int	None
maxConvergeIter	Maximum allowed iterations to get a converged solution.	Int	10
explicit_correction	Deferred correction	Bool	false

Hypre settings

Warning

• These inputs are all case-sensitive.

hypre settings are specified using the following inputs which are read directly by the RTE library. The following inputs are defined using the prefix rte.hypre:

	Description	Type	Default
preconditioner	Type of preconditioner. Options: BoomerAMG	String	None
solver	Type of hypre solver. Options: GMRES BiCGSTAB BoomerAMG	String	None
verbose	Verbosity of hypre.	Int	0
num_krylov	Number of iterations.	Int	50
convergence_tol	Convergence tolerance.	Real	1.0e-4
max_iterations	Maximum number of iterations.	Int	1000

The following inputs are valid when using BoomerAMG as a preconditioner or solver. They must be defined using the prefix rte.hypre:

	Description	Type	Default
bamg_agg_interp_type	See HYPRE_BoomerAMGSetAggInterpType.	Int	4
bamg_agg_num_levels	See HYPRE_BoomerAMGSetAggNumLevels.	Int	0
bamg_agg_pmax_elmts	See HYPRE_BoomerAMGSetAggPMaxElmts.	Int	0
bamg_coarse_relax_type	See HYPRE_BoomerAMGSetCycleRelaxType.	Int	11
bamg_coarsen_type	See HYPRE_BoomerAMGSetCoarsenType.	Int	6
bamg_cycle_type	See HYPRE_BoomerAMGSetCycleType.	Int	1
bamg_down_relax_type	See HYPRE_BoomerAMGSetCycleRelaxType.	Int	11
bamg_interp_type	See HYPRE_BoomerAMGSetInterpType.	Int	0
bamg_keep_transpose	See HYPRE_BoomerAMGSetKeepTranspose.	Int	0
bamg_logging	See HYPRE_BoomerAMGSetLogging.	Int	0
bamg_max_coarse_size	See HYPRE_BoomerAMGSetMaxCoarseSize.	Int	9
bamg_max_iterations	See HYPRE_BoomerAMGSetMaxIter.	Int	1
bamg_max_levels	See HYPRE_BoomerAMGSetMaxLevels.	Int	20
bamg_min_coarse_size	See HYPRE_BoomerAMGSetMinCoarseSize.	Int	1
bamg_num_coarse_sweeps	See HYPRE_BoomerAMGSetCycleNumSweeps.	Int	1
bamg_num_down_sweeps	See HYPRE_BoomerAMGSetCycleNumSweeps.	Int	2
bamg_num_sweeps	See HYPRE_BoomerAMGSetNumSweeps.	Int	2
bamg_num_up_sweeps	See HYPRE_BoomerAMGSetCycleNumSweeps.	Int	2
bamg_pmax_elmts	See HYPRE_BoomerAMGSetPMaxElmts.	Int	4
bamg_precond_tolerance	See HYPRE_BoomerAMGSetTol.	Real	0.0
bamg_relax_order	See HYPRE_BoomerAMGSetRelaxOrder.	Int	1
bamg_relax_type	See HYPRE_BoomerAMGSetRelaxType.	Int	6
bamg_set_restriction	See HYPRE_BoomerAMGSetRestriction.	Int	0
bamg_strong_threshold	See HYPRE_BoomerAMGSetStrongThreshold.	Real	0.57
bamg_trunc_factor	See HYPRE_BoomerAMGSetTruncFactor.	Real	0.1
bamg_up_relax_type	See HYPRE_BoomerAMGSetCycleRelaxType.	Int	11
bamg_variant	See HYPRE_BoomerAMGSetVariant.	Int	0
bamg_verbose	Set BoomerAMG verbosity.	Int	0

Note

This list is likely incomplete because the AMReX / hypre interface continues to evolve.