mod_radiation_dom Module

Grey, absorbing-emitting, non-scattering Discrete Ordinates Method (DOM) radiation solver model.

[Physical Assumptions] - Grey (single wavenumber/band) absorbing-emitting medium. - Non-scattering; no scattering source is included in the transport equations.

[Boundary Condition Assumptions & Limitations] - Wall/open-boundary inflow currently assumes black diffuse behavior, epsilon = 1.0: I_in = (sigma/pi)*T_w^4. - Input emissivity values below 1 are detected and warned about, but diffuse-gray reflection is not implemented in this local independent-ordinate solve. - Symmetry boundaries are simplified/skipped. A true DOM symmetry condition should reflect the ordinate direction through the symmetry plane.

[X-1 Contract] - This module computes and populates only the unreduced local partial absorption-like term kappaG_local in source%qrad. - The radiation driver is responsible for performing the MPI reduction and then locally subtracting the isotropic emission term 4kappasigmaT^4 on all ranks.

This module solves the discretized finite-volume grey DOM transport equations: s_m . grad(I_m) + kappaI_m = kappaI_b where I_b = sigma/pi*T^4. Angular decomposition is used to distribute directions over MPI processes.

Variables

Type	Visibility	Attributes		Name		Initial
real(kind=rk),	private,	parameter	::	pi	=	3.141592653589793_rk
real(kind=rk),	private,	parameter	::	sigma	=	5.670374419e-8_rk	Stefan-Boltzmann constant [W/(m^2*K^4)]

Functions

private function quadrature_octant_weight(quad_type, i, j, k) result(w_ijk)

Returns first-octant normalized weights. Full-space weights are w_ijk*pi/2.

Arguments

Type	Intent	Optional	Attributes		Name
character(len=*),	intent(in)			::	quad_type
integer,	intent(in)			::	i
integer,	intent(in)			::	j
integer,	intent(in)			::	k

Return Value real(kind=rk)

Subroutines

public subroutine radiation_compute_dom(mesh, bc, context, state, source, params)

Main entry point for the DOM radiation model.

Arguments

Type	Intent	Optional	Attributes		Name
type(mesh_t),	intent(in)			::	mesh
type(bc_set_t),	intent(in)			::	bc
type(radiation_context_t),	intent(in)			::	context
type(radiation_state_t),	intent(in)			::	state
type(radiation_source_t),	intent(inout)			::	source
type(case_params_t),	intent(in)			::	params

private subroutine apply_matrix(mesh, diag, coeff, nb, x, ax)

Sparse matrix-vector product for the assembled DOM transport system.

Arguments

Type	Intent	Optional	Attributes		Name
type(mesh_t),	intent(in)			::	mesh
real(kind=rk),	intent(in)			::	diag(:)
real(kind=rk),	intent(in)			::	coeff(:,:)
integer,	intent(in)			::	nb(:,:)
real(kind=rk),	intent(in)			::	x(:)
real(kind=rk),	intent(out)			::	ax(:)

private subroutine get_quadrature(quad_type, n_dirs, s_x, s_y, s_z, w)

Symmetric level-style quadrature lookup/generator.

Arguments

Type	Intent	Optional	Attributes		Name
character(len=*),	intent(in)			::	quad_type
integer,	intent(out)			::	n_dirs
real(kind=rk),	intent(out),		allocatable	::	s_x(:)
real(kind=rk),	intent(out),		allocatable	::	s_y(:)
real(kind=rk),	intent(out),		allocatable	::	s_z(:)
real(kind=rk),	intent(out),		allocatable	::	w(:)

private subroutine solve_pbicgstab(mesh, diag, coeff, nb, rhs, x, max_iter, tol)

Jacobi-preconditioned BiCGStab solver for the unsymmetric DOM transport system.

Arguments

Type	Intent	Optional	Attributes		Name
type(mesh_t),	intent(in)			::	mesh
real(kind=rk),	intent(in)			::	diag(:)
real(kind=rk),	intent(in)			::	coeff(:,:)
integer,	intent(in)			::	nb(:,:)
real(kind=rk),	intent(in)			::	rhs(:)
real(kind=rk),	intent(inout)			::	x(:)
integer,	intent(in)			::	max_iter
real(kind=rk),	intent(in)			::	tol

private subroutine validate_quadrature(n_dirs, s_x, s_y, s_z, w)

Runtime quadrature consistency checks.

Arguments

Type	Intent	Optional	Attributes		Name
integer,	intent(in)			::	n_dirs
real(kind=rk),	intent(in)			::	s_x(:)
real(kind=rk),	intent(in)			::	s_y(:)
real(kind=rk),	intent(in)			::	s_z(:)
real(kind=rk),	intent(in)			::	w(:)