Efficient FDTD algorithm for plane-wave simulation for vertically heterogeneous attenuative media

JafarGandomi, Arash; Takenaka, Hiroshi

doi:10.1190/1.2732555

Cited by 21 publications

(7 citation statements)

References 45 publications

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“…After that, a very prolific bibliography has appeared on electromagnetism [Taflove, 1988, Kunz and Luebbers, 1993, Taflove, 1995]. Since the FDTD method can be classed as a special case of the finite difference method, a standard method for solving PDEs [Strikwerda, 1989], the method has been adapted to solve other wave propagation problems, such as acoustic/aeroacoustic [Wang, 1996, Nguyen, 1996, Botteldooren, 1997, Ostashev et al, 2005, Liu and Albert, 2006 and seismology [Graves, 1996, Kristek and Moczo, 2006, Gandomi and Takenaka, 2007.…”

Section: Suitability Of the Discrete-time Methods For Room Acoustic Smentioning

confidence: 99%

Contributions to discrete-time methods for room acoustic simulation

Escolano-Carrasco

2008

The Journal of the Acoustical Society of America

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Home office worker performance and perception as affected by residential audible distractions through various wall constructions ͓43.55.Rg, 43.50.Qp, 43.55.Hy͔ -Alicia J. Wagner, Department of Architectural Engineering, University of Nebraska, Lincoln, Nebraska 68588, July 2008 (M.S.). This research examines the effects that residential audible distractions have on task performance and subjective perception of home office workers when transmitted across various residential wall constructions. Subjects performed math, verbal, and typing tasks while exposed to 16-h-long sound signals. These signals were generated using four audio filters simulating residential wall constructions providing varying degrees of acoustic attenuation ranging from field sound transmission classes of 36-58. The audio filters were applied to four types of audible distractions: ͑1͒ pop music, ͑2͒ television, ͑3͒ conversation, and ͑4͒ a potpourri of kitchen, pet, and children's noises. A questionnaire was also administered to determine participants' perception of loudness, variation in time, distraction, and annoyance. Statistical analyses indicate that none of the wall constructions or audible distractions significantly affected task performance. However, subjective perception does appear to be related to both factors. The relationship between task performance and subjective perception was also examined, yielding significant results between typing and subjective perception.

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Section: Suitability Of the Discrete-time Methods For Room Acoustic Smentioning

confidence: 99%

Contributions to discrete-time methods for room acoustic simulation

Escolano-Carrasco

2008

The Journal of the Acoustical Society of America

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“…Furumura et al 1998; Bohlen 2002; Furumura 2005). Depending on the purpose of a simulation, it is possible to reduce the computation time by model simplification (Furumura & Takenaka 1996; Takenaka & Kennett 1996; Takenaka et al 1999, 2003; Toyokuni et al 2005; JafarGandomi & Takenaka 2007) or by focusing on some selected phases in a moving zone (Kvasnicka & Zahradník 1996; Hansen & Jacobsen 2002). An efficient strategy is to reduce dispersion error without increasing the computation time.…”

Section: Introductionmentioning

confidence: 99%

Non-standard FDTD for elastic wave simulation: two-dimensionalP-SVcase

JafarGandomi

Takenaka

2009

Geophysical Journal International

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S U M M A R YA scheme for the non-standard finite-difference method in the time-domain (NS-FDTD), 2-Box scheme, is proposed for elastic wave simulations in two dimensions (P-SV ). The method improves the accuracy and efficiently reduces grid dispersion and anisotropy. The proposed non-standard scheme is based on two main operations. The first operation replaces spatial grid spacing and time step by their frequency optimized counterparts, called the correction functions, and the second operation introduces an optimum grid stencil for the finite-difference operator of the 2-D Laplacian. The optimal stencil is obtained by introducing two optimization parameters estimated for a design frequency. Error analysis of the proposed scheme (2-Box scheme) shows that specifying the maximum frequency as the design frequency leads to a significant reduction of the grid dispersion over a wide frequency band. We derive the formulations of grid dispersion and stability condition for the scheme. The grid dispersion is investigated, and it is shown that the proposed scheme reduces not only the grid dispersion but also the grid anisotropy significantly. The grid dispersion is insensitive to the Poisson's ratio and size of the time step within the stability limit. Since the wide spatial stencil of the 2-Box scheme might become difficult to implement at the computational domain boundaries, two additional non-standard schemes-1-Box and 0-Box schemes-are also introduced. The 1-Box scheme uses narrower stencil than the 2-Box scheme, and the 0-Box scheme uses the same stencil as the standard FDTD. Numerical experiments of elastic wave propagation demonstrate the significant superiority of the proposed non-standard schemes over the commonly used standard one. With six grid spacings per minimum wavelength, the 2-Box and 1-Box schemes represent excellent results and the 0-Box scheme has higher accuracy than the standard scheme with seven grid spacings per minimum wavelength.The standard finite-difference in the time-domain (FDTD) is one of the most common techniques used for simulating elastic wave propagation. This technique is popular because it is simple and easy to programme.Various schemes based on the standard FDTD have been reported in geophysical publications. Among them, the staggered-grid scheme introduced by Madariaga (1976) has been a very popular method for modelling elastic wave propagation, both in exploration seismology and in earthquake seismology (e.g. Olsen et al. 2006). The staggered grid can be applied both to the displacement-stress (e.g. Moczo et al. 2002) and velocity-stress finite-difference schemes; however, the later is more common in seismic wave modelling. A velocity-stress finite-difference (FD) scheme, using the staggered grid, with second-order accuracy in space and time, was presented by Virieux (1984Virieux ( , 1986 for SH and P-SV wave propagation. His second-order scheme needs about 10 grid spacings per wavelength for correct modelling. Levander (1988) developed a staggered-grid scheme with fourth-order acc...

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“…Equation (4) is thus a 2.5-D version of the 'Snell's law' which is also mentioned below. Equation (5) could be used for modelling three-component seismic plane waves in vertically heterogeneous media in the time domain (JafarGandomi & Takenaka, 2007;Tanaka & Takenaka, 2005).…”

Section: 5-d Elastodynamic Equation For a Plane-wave Incidencementioning

confidence: 99%