3D numerical simulation for the transient electromagnetic field excited by the central loop based on the vector finite-element method

Li, J H; Zhu, Z. Q.; Liu, S C; Zeng, Shubin

doi:10.1088/1742-2132/8/4/008

Cited by 25 publications

(8 citation statements)

References 23 publications

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“…In the equations 18 and 19, 𝐼 stands for the transmitter current, s is the Laplace variable and is equal to −𝑖𝜔 , 𝜔 stands for angular frequency, 𝜎 is the conductivity of the homogeneous half-space, 𝜆 is the wavenumber, 𝜌 stands for the space between the receiver and the transmitter, (𝑥 ′ , 𝑦 ′ , 𝑧) is the coordinate of the receiver point, 𝐽 0 is the Bessel function of the first kind, zero-order and 𝑇 𝑡𝑒 is the transmission coefficient, which can be found from the following (Li et al 2011):…”

Section: Electromagnetic Field Excited By Rectangular Loopmentioning

confidence: 99%

“…For comparing time and accuracy between tetrahedral and brick elements, we chose a model that could be solved with both and would often be used in electromagnetic interpretations. This model had already been investigated by Li et al (2011) with a brick element. The 3D thin horizontal sheet and rectangular body are common configurations for conductive zones (such as the mineralization of massive pyrite and sulfide body in the ground).…”

Section: Examplesmentioning

confidence: 99%

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Numerical Modelling of TEM Fields by the Edge-Based Finite Element Method Using Tetrahedral Element for Central Rectangular Loops

Aval

Meshinchi-Asl

Mehramuz

2021

Nexo Revista Científica

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In this study, we have implemented an edge-based finite element method for the numerical modeling of the transient electromagnetic method. We took the Helmholtz equation of the electric field as the governing equation for the edge-based finite element analysis. The modeling domain was discretized using linear tetrahedral mesh supported by Whitney-type vector basis functions. We inferred the equations by applying the Galerkin method. The system of equation was solved using a corrected version of the Bi Conjugate Gradient Stabilized Method (BiCGStab) algorithm to reduce the computational time. We obtained numerical solution for electric field in the Laplace domain; then the field was transformed into the time domain using the Gaver-Stehfest algorithm. Following this, the impulse response of the magnetic field was obtained through the Faraday law of electromagnetic induction as it is considerably more stable and computationally more efficient than inversion using the Fourier Transform. 3D geoelectric models were used to investigate the convergence of the edge-based finite element method with the analytic solution. The results are in good agreement with the analytical solution value for two resistivity contrasts in the 3D geoelectric brick model. We also compared the results of tetrahedral elements with the brick element in the 3D horizontal sheet and 3D conductive brick model. The results indicated that these two elements show very similar errors, but tetrahedral reflects fewer relative errors. For the low resistivity geoelectric model, numerical checks against the analytical solution, integral-equation method, and finite-difference time-domain solutions showed that the solutions would provide accurate results.

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Section: Electromagnetic Field Excited By Rectangular Loopmentioning

confidence: 99%

Section: Examplesmentioning

confidence: 99%

Numerical Modelling of TEM Fields by the Edge-Based Finite Element Method Using Tetrahedral Element for Central Rectangular Loops

Aval

Meshinchi-Asl

Mehramuz

2021

Nexo Revista Científica

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“…In this study, the one-dimensional forward solver in the frequency and Laplace domains is the one deduced by Li et al (2011). Figures 1 and 2 show the vertical component of the induced electromagnetic force (EMF) calculated by the GaverStehfest, Euler and Talbot algorithms using doubleprecision arithmetic.…”

Section: Examplesmentioning

confidence: 99%

“…Additionally, the accuracy of Gaver-Stehfest algorithm, when implemented using the typical double-precision arithmetic, can be poor (Raiche, 1987;Effersø et al, 1999;Everett 2009). In spite of these shortcomings, the GaverStehfest algorithm has been widely used in computing time-domain electromagnetic responses (e. g. Everett and Edwards, 1993;Li et al, 2011;Swidinsky et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Two effective inverse Laplace transform algorithms for computing time-domain electromagnetic responses

Farquharson

2015

SEG Technical Program Expanded Abstracts 2015

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The inverse Laplace transform is one of the methods used to obtain time-domain electromagnetic responses in geophysics. The Gaver-Stehfest algorithm has so far been the particular technique used to compute the Laplace transform in the context of transient electromagnetics. However, the accuracy of the Gaver-Stehfest algorithm, even based on double-precision arithmetic, is relatively low at late times due to round-off errors. We therefore turned our attention to two other algorithms for computing inverse Laplace transforms, namely the Euler and Talbot algorithms. Using as examples a rectangular loop source and a horizontal electric dipole source for layered half spaces, these two algorithms, implemented using normal double-precision arithmetic, are shown to have the capacity for efficiently yielding more accurate time-domain responses at late times than the standard Gaver-Stehfest algorithm.

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“…Chen et al investigated a special time-domain electromagnetic system and utilized it for effective detection of unexploded ordnance 8 . Li et al showed the detection and identi cation of small target bodies near the surface by placing the transmitting and receiving coils in a staggered time domain electromagnetic system 9 . Qu et al designed a handheld time domain electromagnetic system to obtain the response characteristics and horizontal position of the target body 10 .…”

Section: Introductionmentioning

confidence: 99%

The Electromagnetic Characteristics of UXO Using the Electromagnetic Method

Lu,

Gao,

Cai

et al. 2024

Preprint

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In the process of UXO removal, effective detection is crucial for the clearance of UXO. This paper investigates the method of TEM to detect UXO, the design optimization of magnetic coupling source and the electromagnetic response characteristics of UXO with different attitudes and depths. The numerical results show that the designed and optimized single-transmitter multiple-receiver TEM detection can not only provide fast localization, but also greatly reduce data processing and improve detection efficiency. Based on the finite element modeling, the electromagnetic response of the target is analyzed in detail with the variation law of position and attitude by combining the information of the fast localization. The field experimental results show that the variation trends of the numerical simulation results of the time-domain electromagnetic response under different attitudes are basically consistent with the measured results. The measuring line response enables the fast localization of suspicious sites by marking them. The planar response establishes the spindle location information. The detection depth has a strong influence on the initial amplitude of the time domain response, while the inclination angle determines the symmetry characteristics of the planar response. This will provide a basis for the design and optimization of the TEM detection system.

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3D numerical simulation for the transient electromagnetic field excited by the central loop based on the vector finite-element method

Cited by 25 publications

References 23 publications

Numerical Modelling of TEM Fields by the Edge-Based Finite Element Method Using Tetrahedral Element for Central Rectangular Loops

Numerical Modelling of TEM Fields by the Edge-Based Finite Element Method Using Tetrahedral Element for Central Rectangular Loops

Two effective inverse Laplace transform algorithms for computing time-domain electromagnetic responses

The Electromagnetic Characteristics of UXO Using the Electromagnetic Method

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