Method of Lines Transpose: An Efficient Unconditionally Stable Solver for Wave Propagation

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• 作者：Matthew Causley ; Andrew Christlieb ; Eric Wolf
• 关键词：Method of lines transpose ; Transverse method of lines ; Implicit methods ; Boundary integral methods ; Alternating direction implicit methods ; ADI schemes
• 刊名：Journal of Scientific Computing
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：70
• 期：2
• 页码：896-921
• 全文大小：
• 刊物类别：Mathematics and Statistics
• 刊物主题：Algorithms; Computational Mathematics and Numerical Analysis; Appl.Mathematics/Computational Methods of Engineering; Theoretical, Mathematical and Computational Physics;
• 出版者：Springer US
• ISSN：1573-7691
• 卷排序：70

文摘

Building upon recent results obtained in Causley and Christlieb (SIAM J Numer Anal 52(1):220–235, 2014), Causley et al. (Math Comput 83(290):2763–2786, 2014, Method of lines transpose: high order L-stable O(N) schemes for parabolic equations using successive convolution, 2015), we describe an efficient second-order, unconditionally stable scheme for solving the wave equation, based on the method of lines transpose (MOL\(^T\)), and the resulting semi-discrete (i.e. continuous in space) boundary value problem. In Causley and Christlieb (SIAM J Numer Anal 52(1):220–235, 2014), unconditionally stable schemes of high order were derived, and in Causley et al. (Method of lines transpose: high order L-stable O(N) schemes for parabolic equations using successive convolution, 2015) a high order, fast \(\mathcal {O}(N)\) spatial solver was derived, which is matrix-free and is based on dimensional-splitting. In this work, are interested in building a wave solver, and our main concern is the development of boundary conditions. We demonstrate all desired boundary conditions for a wave solver, including outflow boundary conditions, in 1D and 2D. The scheme works in a logically Cartesian fashion, and the boundary points are embedded into the regular mesh, without incurring stability restrictions, so that boundary conditions are imposed without any reduction in the order of accuracy. We demonstrate how the embedded boundary approach works in the cases of Dirichlet and Neumann boundary conditions. Further, we develop outflow and periodic boundary conditions for the MOL\(^T\) formulation. Our solver is designed to couple with particle codes, and so special attention is also paid to the implementation of point sources, and soft sources which can be used to launch waves into waveguides.