Diamond difference approximation for MOC. More...

Inheritance diagram for DDMOC:

Collaboration diagram for DDMOC:

Public Member Functions
function	DDMOC (in mesh, in mat)
	Class constructor.
function	setup_group (in obj, in group)
	Setup the equations for a group.
function	setup_octant (in obj, in octant)
	Setup the equations for an octant.
function	setup_angle (in obj, in phi, in ignoredArg)
	Setup the equations for an angle.
function	solve (in obj, in psi_in, in s, in sig, in t, in ignoredArg)
	Solve for the cell-center and outgoing edge fluxes.
Public Attributes
Constant Property	HORZ = 1
Constant Property	VERT = 2
Protected Attributes
Property	d_mesh
	Problem mesh.
Property	d_mat
	Material definitions.
Property	d_quadrature
	Quadrature.
Property	d_mu
	Current mu value.
Property	d_eta
	current eta value
Property	d_ksi
	Current ksi value.
Property	d_alpha
	Weighted diamond difference parameter.
Property	d_mat_map
	Material map.

Detailed Description

Diamond difference approximation for MOC.

In the method of characteristics, the flux is solved for along a track assuming a flat source. In the diamond difference approximation, the average segment flux is taken as an average of the incident and and exiting flux. Similar to the step characteristic (SCMOD), we define the outgoing segment flux

$\psi_{out} = A\psi_{in} + B Q \, ,$

and average segment flux

$\bar{\psi} = \frac{1}{l} \Big ( B \psi_{in} + C Q \Big ) \, ,$

but now

$A = \frac{2-\tau}{2+\tau} \, ,$

$B = \frac{2l}{2+\tau} \, ,$

and

$C = \frac{l^2}{2+\tau} \, ,$

where $ l $ is the segment length and $\tau = \Sigma_t l$ is optical path length.

Unlike the step characteristic approximation, the diamond difference approximation is second order in space but is not guaranteed to yield positive fluxes.

Reference: A. Hebert, Applied Reactor Physics.

See also:: DDMOC

Constructor & Destructor Documentation

function DDMOC	(	in	mesh,
		in	mat
	)

Class constructor.

Set the mesh and material.

Parameters:

mesh	Problem mesh.
mat	Material definitions.

Returns:: Instance of the DDMOC class.

Member Function Documentation

function setup_angle	(	in	obj,
		in	phi,
		in	ignoredArg
	)

Setup the equations for an angle.

Parameters:

phi	Azimuth with respect to x axis.

function setup_group	(	in	obj,
		in	group
	)

Setup the equations for a group.

Here, we'll go through the grid and produce a fine mesh matrix of total cross-sections. This isn't the best thing for memory, but it cuts down a lot on the time within solve.

Parameters:

group Current group.

function setup_octant	(	in	obj,
		in	octant
	)

Setup the equations for an octant.

Parameters:

octant Current octant.

function solve	(	in	obj,
		in	psi_in,
		in	s,
		in	sig,
		in	t,
		in	ignoredArg
	)

Solve for the cell-center and outgoing edge fluxes.

Parameters:

psi_in	Incident flux vector
s	Region isotropic source
sig	Region total cross-section
t	Segment length (includes polar scaling)

Returns:: Segment exit and average angular flux.

Member Data Documentation

Property d_alpha [protected, inherited]

Weighted diamond difference parameter.

Property d_eta [protected, inherited]

current eta value

Property d_ksi [protected, inherited]

Current ksi value.

Property d_mat [protected, inherited]

Material definitions.

Property d_mat_map [protected, inherited]

Material map.

Property d_mesh [protected, inherited]

Problem mesh.

Property d_mu [protected, inherited]

Current mu value.

Property d_quadrature [protected, inherited]

Quadrature.

Constant Property HORZ = 1 [inherited]

Constant Property VERT = 2 [inherited]

The documentation for this class was generated from the following file:

/home/robertsj/Research/matlab_transport_pack/source/DDMOC.m

DDMOC Class Reference

Public Member Functions

Public Attributes

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation