The Double Absorbing Boundary (DAB) is a recently proposed absorbing layer used to truncate an unbounded domain with high-order accuracy. While it was originally designed for time-dependent acoustics and elastodynamics, here the DAB construction is adapted and applied to the 2D Helmholtz equation. Both wave-guide and corner configurations are considered. A high-order spectral finite element scheme is used in order to match the discretization accuracy to the accuracy of the DAB. The DAB scheme is analyzed, and numerical experiments demonstrate its performance.

中文翻译：

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Helmholtz方程的双吸收边界法

双吸收边界 (DAB) 是最近提出的一种吸收层，用于以高阶精度截断无界域。虽然它最初是为瞬态声学和弹性动力学而设计的，但这里的 DAB 结构被改编并应用于 2D Helmholtz 方程。波导和角配置都被考虑。使用高阶谱有限元方案以使离散化精度与 DAB 的精度相匹配。分析了 DAB 方案，并通过数值实验证明了其性能。