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- SP1
and P1
equations are identical.
- SPN
and PN
equations are identical in 1-D slab geometry.
- Rotationally invariant
no ray effects.
- SPN
is a non-convergent method. It is an asymptotic approximation
associated with the diffusion limit. As
N
, the
solution doesn't necessarily converge to the true answer.
- SPN
has almost the same accuracy for lower orders as SN
if the
solution is approximately locally 1-D, but is much cheaper.
- With DSA and LMFG acceleration, SPN
costs
MG + G + 1
diffusion
solutions for every outer iteration.
- Unlike the diffusion equation, the SPN
equations propagate
information at a finite speed. For radiation, this speed approaches
c
from below as the order of approximation is increased.
- Order N
unknowns for SPN
, vs. order N2
unknowns for PN
and SN
.
- In a homogeneous region, SPN
and PN
scalar flux solutions
satisfy same equation, except with different boundary conditions.
Next: SPN Temporal Discretization
Up: Simplified Spherical Harmonics (SPN
Previous: SPN Even-Parity Equation Set
Michael L. Hall