Convergence behavior of second-order transport equations in near-void problems

Journal Article · 13 January 2020 · Journal of Quantitative Spectroscopy and Radiative Transfer

DOI: https://doi.org/10.1016/j.jqsrt.2020.106843 · OSTI ID:1799726

Zhang, Yunhuang ^[1]; Morel, Jim E. ^[2]; Ragusa, Jean C. ^[2]

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1. Texas A & M Univ., College Station, TX (United States); OSTI
2. Texas A & M Univ., College Station, TX (United States)

In this article, a newly developed second-order least-squares form of the S_N equations is tested in 3-D with both thin-slab problems and the PECOS vehicle re-entry problem. Its performance in voids and near-voids is then compared to that of the SP_N, even-parity S_N, and self-adjoint angular flux (SAAF) methods through convergence tests in these two problems. A rebalance scheme is also proposed for the least-squares S_N to regain particle balance for this generally non-conservative form. Our results indicate that the least-squares S_N method is capable of producing accurate results in these kinds of problems where the SP_N, even-parity S_N fail to produce trustworthy results. While SAAF can produce results comparable with least-squares S_N, it can be ill-posed in some extreme cases.

• Research Organization: University of Texas, Austin, TX (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: FC52-08NA28615
• OSTI ID: 1799726
• Journal Information: Journal of Quantitative Spectroscopy and Radiative Transfer, Journal Name: Journal of Quantitative Spectroscopy and Radiative Transfer Journal Issue: C Vol. 244; ISSN 0022-4073
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English