An approximate theory for the scattering of an incident plane P wave into tube waves in a fluid-filled borehole drilled through two homogeneous half-spaces is proposed in this paper. This theory is in excellent agreement with the zero frequency formulation (White, 1983) for frequencies below hundreds of Hertz (in the range of conventional crosshole or VSP experiments) and flnite difference simu...

NHA The Fibroscan device (Echosens) works by measuring shear wave velocity. In this technique, a 50-MHz wave is passed into the liver from a small transducer on the end of an ultrasound probe (Figure 1). The probe also has a transducer on the end that can measure the velocity of the shear wave (in meters per second) as this wave passes through the liver. The shear wave velocity can then be conv...

in this article, vibration analysis of an euler-bernoulli beam resting on a pasternak-type foundation is studied. the governing equation is solved by using a spectral finite element model (sfem). the solution involves calculating wave and time responses of the beam. the fast fourier transform function is used for temporal discretization of the governing partial differential equation into a set ...

shear wave velocity is a basic engineering tool required to define dynamic properties of soils. in many instances it may be preferable to determine vs indirectly by common in-situ tests, such as the standard penetration test. many empirical correlations based on the standard penetration test are broadly classified as regression techniques. however, no rigorous procedure has been published for c...

A new two-dimensional approximate Riemann solver has been developed that obtains fluxes on grid faces via wave decomposition. By utilizing information propagating in the velocity-difference directions rather than in the grid-normal directions, this flux function more appropriately interprets and hence more sharply resolves shock and shear waves when they lie oblique to the grid. The model uses ...

[1] The gauge condition relating the electromagnetic potentials of shear Alfvén waves is one of the key governing equations in simulations of low-frequency waves in the Earth’s magnetosphere. Mottez [2013] suggests that the gauge condition used in Watt and Rankin [2010] is inappropriate for the case where the perpendicular wave number of the shear Alfvén wave varies as a function of distance al...

We investigate the interaction of a small-amplitude internal gravity wave packet in a rotating fluid with a baroclinic shear flow. Ray equations and three-dimensional direct numerical simulations of the Boussinesq equations are solved for this purpose. The shear flow has a simple structure and depends separately on the vertical and horizontal coordinates. We focus on the situation where the int...

The role of nonnormality in the overreflection of gravity waves is investigated. In the limit of weak stratification, wave packets having a critical level inside a shear layer of finite depth are reflected with amplified energy. This process, which exhibits the characteristics of stimulated emission, occurs in three stages: first, the incoming wave enters the shear layer and excites nonpropagat...

the seismic anisotropy is a subject of interest for seismologists and geologists. the information of seismic anisotropy has significant role in geology interpretations (savage, 1999). in this study, we have investigated the upper crust anisotropy in bam area by means of shear wave splitting sg phase. we have selected more than three hundred aftershocks from iiees local temporary seismic network...

laboratory data, which relate the liquefaction resistance of firoozkooh sand and non-plastic silt mixtures to shear wave velocity are presented and compared to liquefaction criteria derived from seismic field measurements by andrus and stokoe [1]. in the work described herein, cyclic triaxial and resonant column tests were conducted on specimens of clean sand and sand-silt mixtures with silt co...