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A nonsplit complex frequency-shifted PML based on recursive integration for FDTD modeling of elastic waves

Francis H. Drossaert and Antonios Giannopoulos
A nonsplit complex frequency-shifted PML based on recursive integration for FDTD modeling of elastic waves
Geophysics (April 2007) 72 (2): T9-T17

Abstract

In finite-difference time-domain (FDTD) modeling of elastic waves, absorbing boundary conditions are used to mitigate undesired reflections that can arise at the model's truncation boundaries. The perfectly matched layer (PML) is generally considered to be the best available absorbing boundary condition. An important but rarely addressed limitation of current PML implementations is that their performance is severely reduced when waves are incident on the PML interface at near-grazing angles. In addition, very low frequency waves as well as evanescent waves could cause spurious reflections at the PML interface. In electromagnetic modeling, similar problems are circumvented by using a complex frequency-shifted stretching function in the PML formulas. However, in elastic-wave modeling using the conventional PML formulation--based on splitting the velocity and stressfields--it is difficult to adopt a complex frequency--shifted stretching function. We present an alternative implementation of a PML that is based on recursive integration and does not require splitting of the velocity and stress fields. Modeling results show that the performance of our implementation using a standard stretching function is identical to that of the convention-al split-field PML. Then we show that the new PML can be modified easily to include the complex frequency-shifted stretching function. Results of models with an elongated domain show that this modification can substantially improve the performance of the PML boundary condition. An efficient implementation of the new PML requires less memory than the conventional split-field PML, and, therefore, is a very attractive alternative to the conventional PML. By adopting the complex frequency-shifted stretching function, the PML can accommodate a wide variety of model problems, and hence it is more generic.


ISSN: 0016-8033
EISSN: 1942-2156
Coden: GPYSA7
Serial Title: Geophysics
Serial Volume: 72
Serial Issue: 2
Title: A nonsplit complex frequency-shifted PML based on recursive integration for FDTD modeling of elastic waves
Affiliation: University of Edinburgh, Institute for Infrastructure and Environment, Edinburgh, United Kingdom
Pages: T9-T17
Published: 200704
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 23
Accession Number: 2007-114229
Categories: Applied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by Society of Exploration Geophysicists, Tulsa, OK, United States
Update Code: 200747
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