Robust and Accurate Filtered Spherical Harmonics Expansions for Radiative Transfer
- ORNL
- Texas A&M University
We present a novel application of lters to the spherical harmonics (PN) expansion for radiative transfer problems in the high energy density regime. The lter we use is based on non-oscillatory spherical splines and a lter strength chosen to (i) preserve the equilibrium di usion limit and (ii) vanish as the expansion order tends to in nity. Our implementation is based on modi ed equations that are derived by applying the lter after every time step in a simple rst-order time integration scheme. The method is readily applied to existing codes that solve the PN equations. Numerical results demonstrate that the solution to the ltered PN equations are (i) more robust and less oscillatory than standard PN solutions and (ii) more accurate than discrete ordinates solutions of comparable order. In particular, the ltered P7 solution demonstrates comparable accuracy to an implicit Monte Carlo solution for a benchmark hohlraum problem in 2-D Cartesian geometry.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 982115
- Journal Information:
- Journal of Computational Physics, Vol. 229, Issue 16; ISSN 0021-9991
- Country of Publication:
- United States
- Language:
- English
Similar Records
Simulating Radiative Transfer with Filtered Spherical Harmonics
The application of finite elements and space-angle synthesis to the anisotropic steady state Boltzmann (transport) equation. Master's thesis