arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2409.06162math.NAcs.NAmath-phmath.MP
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一种适用于连续扩散与离散输运离散化的k本征值加速二阶矩方法

A Second Moment Method for k-Eigenvalue Acceleration with Continuous Diffusion and Discontinuous Transport Discretizations

Zachary K. Hardy, Jim E. Morel, Jan I. C. Vermaak

AI总结:

针对二阶矩方法作为k本征值加速方案研究不足的问题,本研究采用先进离散化技术将其拓展至实际反应堆问题,验证了其在非结构化网格复杂反应堆问题上的计算效率优势。

摘要:

二阶矩方法是一种线性加速技术,它将输运方程与带有依赖于输运的加性闭合项的扩散方程耦合起来。与扩散合成加速(diffusion synthetic acceleration)不同,由此得到的低阶扩散方程的离散化可以独立于输运离散化进行;与准扩散(quasi-diffusion)方法不同,该低阶扩散方程是对称正定的。虽然已有研究表明该方法在固定源问题和含时问题的迭代性能上与准扩散方法相当,但由于人们认为其产生的非齐次源会导致问题不适定,它作为本征值问题加速方案的研究在很大程度上尚未开展。近期,有研究针对本征值问题的二阶矩方法开展了初步可行性研究,结果显示其性能与准扩散方法相当,且鲁棒性优于扩散合成加速。本研究采用最先进的离散化技术,将初始研究拓展至更贴近实际的反应堆问题。本文结果表明,在带有非结构化网格的复杂反应堆问题上,二阶矩方法的计算效率高于其他替代方法。

英文摘要:

The second moment method is a linear acceleration technique which couples the transport equation to a diffusion equation with transport-dependent additive closures. The resulting low-order diffusion equation can be discretized independent of the transport discretization, unlike diffusion synthetic acceleration, and is symmetric positive definite, unlike quasi-diffusion. While this method has been shown to be comparable to quasi-diffusion in iterative performance for fixed source and time-dependent problems, it is largely unexplored as an eigenvalue problem acceleration scheme due to thought that the resulting inhomogeneous source makes the problem ill-posed. Recently, a preliminary feasibility study was performed on the second moment method for eigenvalue problems. The results suggested comparable performance to quasi-diffusion and more robust performance than diffusion synthetic acceleration. This work extends the initial study to more realistic reactor problems using state-of-the-art discretization techniques. Results in this paper show that the second moment method is more computationally efficient than its alternatives on complex reactor problems with unstructured meshes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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