Experimental observation of surface wave propagation for a transversely isotropic medium

Geophysics ◽  
1995 ◽  
Vol 60 (1) ◽  
pp. 185-190 ◽  
Author(s):  
Chih‐Hsiung Chang ◽  
Gerald H. F. Gardner ◽  
John A. McDonald
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Surface Waves ◽  
Transversely Isotropic ◽  
Insulation Material ◽  
Velocity Anisotropy ◽  
Vertical Seismic Profiling ◽  
Surface Wave Propagation ◽  
Transversely Isotropic Media ◽  
Isotropic Media

Velocity anisotropy of surface‐wave propagation in a transversely isotropic solid has been observed in a laboratory study. In this study, Phenolite™, an electrical insulation material, was used as the transversely isotropic media (TIM), and a vertical seismic profiling (VSP) geometry was used to record seismic arrivals and to separate surface waves from shear waves. Results show that surface waves that propagate with different velocities exist at certain directions.

Wave propagation in transversely isotropic elastic media - II. Surface waves

1989 ◽  
Vol 422 (1862) ◽  
pp. 67-101 ◽  
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Surface Waves ◽  
Plane Waves ◽  
Transversely Isotropic ◽  
Theoretical Background ◽  
Clear Understanding ◽  
Elastic Media ◽  
Surface Wave Propagation ◽  
Anisotropic Elastic

The treatment of homogeneous plane waves given in part I provides the basis for the detailed study of the nature of surface-wave propagation in transversely isotropic elastic media presented in this paper. The investigation is made within the framework of the existence theorem of Barnett and Lothe and the developments underlying its proof. The paper begins with a survey of this essential theoretical background, outlining in particular the formulation of the secular equation for surface waves in the real form F(v) = 0, F(v) being a nonlinear combination of definite integrals involving the acoustical tensor Q (⋅) and the associated tensor R (⋅,⋅) introduced in part I. The calculation of F(v) for a transversely isotropic elastic material is next undertaken, first, in principle, for an arbitrary orientation of the axis of symmetry, then for the α and β configurations, shown in part I to contain all the exceptional transonic states. In the rest of the paper the determination of F(v) is completed, in closed form, for the α and β configurations and followed in each case by a discussion of the properties of F(v) and illustrative numerical results. This combination of analysis and computation affords a clear understanding of surface-wave behaviour in the exceptional configurations comprising, in the classification of part I, cases 1, 2 and 3. The findings for case 1 exhibit continuous transitions, within the α configurations, between subsonic and supersonic surface-wave propagation. Those for case 3 prove that there are discrete orientations of the axis for which no genuine surface wave can propagate and that this degeneracy typically has a marked influence on surface-wave properties in a sizeable sector of neighbouring β configurations. Neither effect appears in previous accounts of surface-wave propagation in anisotropic elastic media.

Surface waves on water of non-uniform depth

1958 ◽  
Vol 4 (6) ◽  
pp. 607-614 ◽  
Author(s):  
Joseph B. Keller
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Surface Waves ◽  
Linear Theory ◽  
Gravity Waves ◽  
Geometrical Optics ◽  
Surface Wave Propagation ◽  
Special Cases

Gravity waves occur on the surface of a liquid such as water, and the manner in which they propagate depends upon its depth. Although this dependence is described in principle by the equations of the ‘exact linear theory’ of surface waves, these equations have not been solved except in some special cases. Therefore, oceanographers have been unable to use the theory to describe surface wave propagation in water whose depth varies in a general way. Instead they have employed a simplified geometrical optics theory for this purpose (see, for example, Sverdrup & Munk (1944)). It has been used very successfully, and consequently various attempts, only partially successful, have been made to deduce it from the exact linear theory. It is the purpose of this article to present a derivation which appears to be satisfactory and which also yields corrections to the geometrical optics theory.

Surface Wave Propagation in Thin Silver and Aluminium Films

2005 ◽  
Vol 60 (11-12) ◽  
pp. 789-796
Author(s):  
Anouar Njeh ◽  
Nabil Abdelmoula ◽  
Hartmut Fuess ◽  
Mohamed Hédi Ben Ghozlen
Keyword(s):  
Thin Films ◽  
Wave Propagation ◽  
Surface Wave ◽  
Surface Waves ◽  
Acoustic Waves ◽  
Frequency Interval ◽  
Constant Frequency ◽  
Surface Wave Propagation ◽  
Coated Materials ◽  
Bulk Waves

Three kinds of acoustic waves are known: bulk waves, pseudo-surface waves and surface waves. A plane wave section of a constant-frequency surface of a film serves as a hint for the expected nature. Calculations based on slowness curves of films reveal frequency ranges where each type of acoustic waves is predominant. Dispersion curves and displacement acoustic waves are calculated and commented in each frequency interval for different coated materials. Both dispersion and sagittal elliptical displacement are sensitive and depend on diagrams mentioned above. Silver and aluminium thin films having different anisotropy ratios, namely 2.91 and 1.21, are retained for illustration.

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