• Title/Summary/Keyword: CFS-PML

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Application and Improvement of Complex Frequency Shifted Perfectly Matched Layers for Elastic Wave Modeling in the Frequency-domain (주파수영역 탄성파모델링에 대한 CFS-PML경계조건의 적용 및 개선)

  • Son, Min-Kyung;Cho, Chang-Soo
    • Geophysics and Geophysical Exploration
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    • v.15 no.3
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    • pp.121-128
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    • 2012
  • Absorbing boundary conditions are used to mitigate undesired reflections that can arise at the model's truncation boundaries. We apply a complex frequency shifted perfectly matched layer (CFS-PML) to elastic wave modeling in the frequency domain. Modeling results show that the performance of our implementation is superior to other absorbing boundaries. We consider the coefficients of CFS-PML to be optimal when the kinetic energy becomes to the minimum, and propose the modified CFS-PML that has the CFS-PML coefficient ${\alpha}_{max}$ defined as a function of frequency. Results with CFS-PML and modified CFS-PML are significantly improved compared with those of the classical PML technique suffering from large spurious reflections at grazing incidence.

Application of ADE-PML Boundary Condition to SEM using Variational Formulation of Velocity-Stress 3D Wave Equation (속도-응력 변분식을 이용한 3차원 SEM 탄성파 수치 모사에 대한 ADE-PML경계조건의 적용)

  • Cho, Chang-Soo;Son, Min-Kyung
    • Geophysics and Geophysical Exploration
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    • v.15 no.2
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    • pp.57-65
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    • 2012
  • Various numerical methods in simulation of seismic wave propagation have been developed. Recently an innovative numerical method called as the Spectral Element Method (SEM) has been developed and used in wave propagation in 3-D elastic media. The SEM that easily implements the free surface of topography combines the flexibility of a finite element method with the accuracy of a spectral method. It is generally used a weak formulation of the equation of motion which are solved on a mesh of hexahedral elements based on the Gauss-Lobatto-Legendre integration rule. Variational formulations of velocity-stress motion are newly modified in order to implement ADE-PML (Auxiliary Differential Equation of Perfectly Matched Layer) in wave propagation in 3-D elastic media, because a general weak formulation has a difficulty in adapting CFS (Complex Frequency Shifted) PML (Perfectly Matched Layer). SEM of Velocity-Stress motion having ADE-PML that is very efficient in absorbing waves reflected from finite boundary is verified with simulation of 1-D and 3-D wave propagation.