The orographic gravity wave drag produced in flow over an axisymmetric mountain when both vertical wind shear and non-hydrostatic effects are important was calculated using a semi-analytical two-layer linear model, including unidirectional or directional constant wind shear in a layer near the surface, above which the wind is constant. The drag behaviour is determined by partial wave reflection...

Certain diseases produce changes in the elastic properties of soft tissues. Conventional imaging modalities in some cases have poor performance in diagnosing these types of diseases. To overcome this problem, elastographic imaging techniques that focus on evaluating the elastic properties of tissues, i.e., tissue stiffness, have been developed in the past three decades. Soft tissues, however, i...

The radiation of elastic waves from a localized source is observed experimentally in a two-dimensional plasma crystal. An initial shear stress applied by a laser forms a small dipole source. The emerging complex wave pattern is shown to consist of outgoing compressional and shear wave pulses. Subsequent structures are identified as inward-going waves due to the finite size of the source region,...

In this paper, propagation of shear waves in a non-homogeneous anisotropic incompressible, magnetic field, gravity field and initially stressed medium has been studied. Analytical analysis reveals that the velocity of propagation of the shear waves depends upon the direction of propagation, the anisotropy, magnetic field, gravity field, non-homogeneity of the medium, and the initial stress. The...

The rotation of the Earth leads to a change in the equation of motion because of the Coriolis force. We study how Earth’s rotation affects elastic wave propagation. We show that the Coriolis force does not deflect seismic rays because the medium that carries the waves moves with Earth’s rotation. However, Earth’s rotation causes a weak traverse component of P-waves and a weak longitudinal compo...

The generation of shear flow by drift waves is an important area of investigation. In a recent paper @Chen et al., Phys. Plasmas 7, 3129 ~2000!# an elegant formalism was developed for the generation of shear/zonal flows by drift waves in a toroidal plasma. The study of shear flow generation in fluids and plasmas is put into perspective. In this paper it is shown how a simple slab geometry analy...

The temporal evolution of drift-Alfv en waves in a plasma ow with homogeneous shear is studied as an initial value problem without the use of spectral expansion in time. It is shown that the conventional modal structure of the drift-Alfv en instability (as well as drift and Alfv en waves) pertains only in the initial stage of its evolution. For larger times, non-modal e ects due to the velocity...

Picosecond laser ultrasonic techniques for acoustic wave generation and detection have been employed to probe shear acoustic waves in liquid glycerol at gigahertz frequencies. The experimental approach uses a unique laser pulse shaping technique and a crystallographically canted metal layer to generate frequency-tunable transverse acoustic waves, and uses time-domain coherent Brillouin scatteri...

To investigate the propagation of flexural waves in a borehole surrounded by an azimuthally anisotropic hard formation, we made an ultrasonic borehole model of Delabole slate with very strong anisotropy. The axial and azimuthal acoustic fields generated by a dipole source were measured in the fluid-filled borehole. The results show that there are three dominant wave modes: fast and slow flexura...

We study the generation of surface waves on water as a bifurcation phenomenon. For a critical wind-speed there appear traveling wave solutions. While linear waves do not transport mass (in the mean), nonlinear effects create a shear-flow and result in a net mass transport in the direction of the wind. We derive an asymptotic formula for the average tangential velocity along the free surface. Nu...