Null-Field Preconditioner With Selected Far-Field Contribution for 3-D Full-Wave EFIE

2016 ◽  
Vol 64 (11) ◽  
pp. 4923-4928 ◽  
Author(s):  
Yoginder Kumar Negi ◽  
N. Balakrishnan ◽  
Sadasiva M. Rao ◽  
Dipanjan Gope
Keyword(s):  
Far Field ◽  
Null Field ◽  
Full Wave

scholarly journals AN HYBRID MODEL FOR THE EVALUATION OF THE FULL-WAVE FAR-FIELD RADIATED EMISSION FROM PCB TRACES

2010 ◽  
Vol 101 ◽  
pp. 125-138 ◽  
Author(s):  
Andrea Gaetano Chiariello ◽  
Giovanni Miano ◽  
Antonio Maffucci
Keyword(s):  
Hybrid Model ◽  
Far Field ◽  
Full Wave ◽  
Radiated Emission

Numerical computation of individual far‐field arrivals excited by an acoustic source in a borehole

Geophysics ◽  
1985 ◽  
Vol 50 (5) ◽  
pp. 852-866 ◽  
Author(s):  
Andrew L. Kurkjian
Keyword(s):  
Numerical Computation ◽  
The Body ◽  
Body Waves ◽  
Head Wave ◽  
Far Field ◽  
Trapped Mode ◽  
Full Waveform ◽  
Full Wave ◽  
Head Waves ◽  
Strong Shear

In this paper, I model the acoustic logging problem and numerically compute individual arrivals at far‐field receivers. The ability to compute individual arrivals is useful for examining the sensitivities of each arrival to various factors of interest, as opposed to examining the full waveform as a whole. While the numerical computation of the mode arrivals (Peterson, 1974) and the numerical computation of the first head waves (Tsang and Rader, 1979) have been previously reported, the numerical computation of the entire set of head‐wave arrivals is new and is the major contribution of this paper. Following Roever et al. (1974) and others, the full wave field is represented as a sum of contributions from both poles and branchcuts in the complex wavenumber plane. The pole contributions correspond to mode arrivals while the branch cuts are associated with the body waves (i.e., head waves). Both the pole and branch cut contributions are computed numerically and results are presented for the cases of a slow and a fast formation. The shear event in the slow formation is found to be relatively small, consistent with observations in measured data. Contrary to existing knowledge, the shear event in the fast formation is also relatively small. The apparent strong shear arrival in the full waveforms is due primarily to the trapped mode pole in the vicinity of cutoff.

Full‐wave modeling of the transmission of sound over theater seats: Far‐field investigation

1992 ◽  
Vol 92 (4) ◽  
pp. 2347-2347
Author(s):  
Dominique J. Chéenne ◽  
Robert D. Kubik ◽  
Robert C. Maher ◽  
Ezekiel Bahar
Keyword(s):  
Field Investigation ◽  
Far Field ◽  
Wave Modeling ◽  
Full Wave

A far-field scattering model in textured polycrystals with ellipsoidal grains of arbitrary crystal symmetry

2020 ◽  
Vol 25 (5) ◽  
pp. 1155-1171
Author(s):  
Gaofeng Sha
Keyword(s):  
Elastic Waves ◽  
Field Approximation ◽  
Crystal Symmetry ◽  
Polycrystalline Materials ◽  
Far Field ◽  
Efficient Tool ◽  
Practical Applications ◽  
Full Wave ◽  
Non Destructive ◽  
High Computational Efficiency

Modeling the scattering-induced attenuation of elastic waves in heterogeneous polycrystals has practical applications in seismology and non-destructive evaluation. However, attenuation modeling for polycrystals with preferred crystallographic orientation (statistically anisotropic or textured polycrystals) has not been well studied. The far-field approximation (FFA) model, which is applicable for arbitrary crystal (triclinic) symmetry and valid for the whole frequency range (Rayleigh region, stochastic regime, and geometric region), has been reported for texture-free polycrystalline materials. This paper extends the FFA model to textured polycrystals with ellipsoidal grains of arbitrary crystal symmetry. This FFA model for textured polycrystals encompasses two advantages: a simple form of dispersion equation and high computational efficiency. Furthermore, this FFA model can predict both the attenuation and phase velocity of elastic waves in textured polycrystals. The FFA model in this study has also been validated by comparison with the full-wave second-order attenuation model on textured polycrystals of triclinic grains. This work provides a simple and efficient tool to predict the elastic wave behavior in heterogeneous polycrystalline materials.

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