Linear characteristic method for spatially discretizing the discrete ordinates equations in (X,Y)-geometry
A new linear characteristic (LC) spatial differencing scheme for the discrete-ordinates equations in (x,y) geometry is described, and numerical comparisons are given with the diamond difference (DD) method. The LC method is more stable with mesh size and is generally much more accurate than the DD method on both fine and coarse meshes, for eigenvalue and deep-penetration problems. The LC method is based on computations involving the exact solution of a cell problem that has spatially linear boundary conditions and interior source. The LC method is coupled to the diffusion synthetic acceleration (DSA) algorithm in that the linear variations of the source are determined in part by the results of the DSA calculation from the previous inner iteration. An inexpensive negative-flux fixup is used which has very little effect on the accuracy of the solution. The storage requirements for LC are essentially the same as that for DD, while the computational times for LC are generally less than twice the DD computational times for the same mesh. This increase in computational cost is offset if one computes LC solutions on somewhat coarser meshes than DD; the resulting LC solutions are still generally much more accurate than the DD solutions. 4 figures, 6 tables.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6900119
- Report Number(s):
- LA-UR-81-101; CONF-810415-3; TRN: 81-004424
- Resource Relation:
- Conference: ANS/ENS joint topical meeting on mathematical methods in nuclear engineering, Munich, F.R. Germany, 27 Apr 1981
- Country of Publication:
- United States
- Language:
- English
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DISCRETE ORDINATE METHOD
COMPARATIVE EVALUATIONS
NEUTRON TRANSPORT THEORY
TWO-DIMENSIONAL CALCULATIONS
SHIELDING
NEUTRON TRANSPORT
ACCURACY
COMPUTER CALCULATIONS
EIGENVALUES
ITERATIVE METHODS
NEUTRON DIFFUSION EQUATION
DIFFERENTIAL EQUATIONS
EQUATIONS
NEUTRAL-PARTICLE TRANSPORT
RADIATION TRANSPORT
TRANSPORT THEORY
654003* - Radiation & Shielding Physics- Neutron Interactions with Matter