A multigrid method for S sub N calculations in x-y geometry
Conference
·
· Transactions of the American Nuclear Society; (USA)
OSTI ID:5560762
- Lawrence Livermore National Lab., CA (USA)
The standard source iteration method for obtaining iterative solutions of S{sub N} problems is known to converge slowly in optically thick, diffusive regions. Consequently, a class of acceleration schemes, synthetic methods, has been developed that has greatly increased the efficiency of S{sub N} calculations. The basic principle in the synthetic method is to use a suitable low-order operator to accelerate an iteration with a high-order operator. Initially, the low-order operator was a diffusion operator, which yielded a method known as diffusion-synthetic acceleration (DSA). Unfortunately, for the DSA method to be implemented in a stable fashion, a particular set of acceleration equations is required, which may be difficult to solve efficiently for complicated discretization schemes (e.g., nodal methods). Thus, in x-y geometry, DSA has only been implemented for the diamond-differenced S{sub N} equations. An effective means of accelerating iteration schemes, which (until now) has been almost exclusively applied to elliptic equations, is the multigrid method. The authors present a multigrid algorithm for solving low-order transport operators; specifically, a multigrid algorithm is used to solve the pseudo-S{sub 2} (PS{sub 2}) equations, which result from a BPA method that was presented previously.
- OSTI ID:
- 5560762
- Report Number(s):
- CONF-880601--
- Conference Information:
- Journal Name: Transactions of the American Nuclear Society; (USA) Journal Volume: 56
- Country of Publication:
- United States
- Language:
- English
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