Energy conservation equations and interaction contributions at a structural interface between two dissipative media. Numerical experiments

Johana Brokesova & Vlastislav Cerveny

Summary

Energy conservation equations at a plane interface between two dissipative media are studied, assuming a plane elastic wave incident on it. In dissipative media, the conservation equations are more complex than in non-dissipative media. Among others, they contain the interaction contributions. The main purpose of this paper is to investigate numerically the energy conservation equations and the interaction contributions. An attempt is done to a find whether some energy-based quantities could be used in the local criteria for selection of proper "downgoing" and "upgoing" reflected and transmitted waves. The specification of downgoing and upgoing waves in dissipative media is not straightforward. For non-dissipative media, such energy-based criteria have been well known, but for dissipative media the general criteria have not yet been proposed. To make the numerical investigation more transparent, only the simplest reflection/transmission problem, corresponding to an SH incident wave, is considered. Numerical experiments offer certain interesting conclusions, but no one of these conclusions can be directly applied in the selection criteria. A suitable selection criterion is proposed for a special, but very important case, in which the angle of incidence equals the attenuation angle. The proposed selection criterion may be used quite safely both in isotropic and anisotropic media.

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In: Seismic Waves in Complex 3-D Structures, Report 11, pp. 315-336, Dep. Geophys., Charles Univ., Prague, 2001.
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