Application of perfectly matched layers to the transient modeling of subsurface EM problems

Geophysics ◽  
1997 ◽  
Vol 62 (6) ◽  
pp. 1730-1736 ◽  
Author(s):  
Yong H. Chen ◽  
Weng Cho Chew ◽  
Michael L. Oristaglio
Keyword(s):  
Staggered Grid ◽  
Dipole Source ◽  
Perfectly Matched Layers ◽  
Absorbing Boundary ◽  
Simulation Region ◽  
Modified Equations ◽  
Lossy Media ◽  
Physical Phenomena ◽  
Homogeneous Media ◽  
Matched Layers

Berenger's perfectly matched layers (PML) have been found to be very efficient as a material absorbing boundary condition (ABC) for finite‐difference time‐domain (FDTD) modeling of lossless media. In this paper, we apply the PML technique to truncate the simulation region of conductive media. Examples are given to show some possible applications of the PML technique to subsurface problems with lossy media. To apply the PML ABC for lossy media, we first modify the original 3-D Maxwell's equations to achieve PML at the boundaries of the simulation region. The modified equations are then solved by using a staggered grid with a central‐differencing scheme. A 3-D FDTD code has been written on the basis of our PML formulation to simulate the electromagnetic field responses of a dipole source in both lossless and lossy media. The code is first tested against analytical solutions for homogeneous media of different losses and then applied to some subsurface problems, such as a geological fault and a buried gas tank. Very interesting propagation and scattering phenomena are observed from the simulation results. Some analyses are also given to explain the physical phenomena of the calculated waveforms.

scholarly journals A Comparative Study of Absorbing Layer Methods to Model Radiating Boundary Conditions for the Wave Propagation in Infinite Medium

2018 ◽  
Vol 7 (3.35) ◽  
pp. 25
Author(s):  
Ravi Shankar Badry ◽  
Maruthi Kotti ◽  
Pradeep Kumar Ramancharla
Keyword(s):  
Boundary Conditions ◽  
Absorbing Boundary Conditions ◽  
Computational Time ◽  
Perfectly Matched Layers ◽  
Implementation Cost ◽  
Absorbing Boundary ◽  
Propagating Waves ◽  
Unbounded Media ◽  
Absorbing Layer ◽  
Matched Layers

Radiating boundary condition is an important consideration in the finite element modelling of unbounded media. Absorbing layer techniquessuch as Perfectly Matched Layers (PML) and Absorbing Layers by Increasing Damping (ALID) becoming popular as they are efficient in absorbing outward propagating waves energy. In this study, a comparative analysis has been carried out between PML and ALID+VABC (Absorbing Boundary conditions for Viscoelastic materials) methods. The methods are analyzedusing LS-DYNAexplicit solver and the efficiency is compared with standard solutions.The study concluded that PML requires less number of elements to model the boundary conditions when compared with ALID+VABC. But PMLrequires a smaller element length which increases overall computational time. Both the methods are efficient in absorbing the wave energy. However, PML requires additional implementation cost to solve the complex equations. 

scholarly journals Well-Designed Termination Wall of Perfectly Matched Layers for ATS-FDTD Method

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Ju Ge ◽  
Liping Gao ◽  
Rengang Shi
Keyword(s):  
Boundary Condition ◽  
Numerical Experiments ◽  
Fdtd Method ◽  
Difference Schemes ◽  
Absorbing Boundary Condition ◽  
Perfectly Matched Layers ◽  
Absorbing Boundary ◽  
Matched Layers ◽  
Special Difference

This paper presents a well-designed termination wall for the perfectly matched layers (PML). This termination wall is derived from Mur’s absorbing boundary condition (ABC) with special difference schemes. Numerical experiments illustrate that PML and the termination wall works well with ATS-FDTD(Shi et al. 2015). With the help of termination wall, perfectly matched layers can be decreased to two layers only; meanwhile, the reflection error still reaches -60[dB] when complex waveguide is simulated by ATS-FDTD.

PERFECTLY MATCHED LAYERS FOR ELASTODYNAMICS: A NEW ABSORBING BOUNDARY CONDITION

1996 ◽  
Vol 04 (04) ◽  
pp. 341-359 ◽  
Author(s):  
W.C. CHEW ◽  
Q.H. LIU
Keyword(s):  
Boundary Condition ◽  
Half Space ◽  
Electromagnetic Waves ◽  
Three Dimensional ◽  
Absorbing Boundary Condition ◽  
Perfectly Matched Layers ◽  
Absorbing Boundary ◽  
Multiple Data ◽  
Open Region ◽  
Matched Layers

The use of perfectly matched layers (PML) has recently been introduced by Berenger as a material absorbing boundary condition (ABC) for electromagnetic waves. In this paper, we will first prove that a fictitious elastodynamic material half-space exists that will absorb an incident wave for all angles and all frequencies. Moreover, the wave is attenuative in the second half-space. As a consequence, layers of such material could be designed at the edge of a computer simulation region to absorb outgoing waves. Since this is a material ABC, only one set of computer codes is needed to simulate an open region. Hence, it is easy to parallelize such codes on multiprocessor computers. For instance, it is easy to program massively parallel computers on the SIMD (single instruction multiple data) mode for such codes. We will show two- and three-dimensional computer simulations of the PML for the linearized equations of elastodynamics. Comparison with Liao’s ABC will be given.

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