We analyse the non-linear propagation and dissipation of axisymmetric waves in accretion discs using the ZEUS-2D hydrodynamics code. The waves are numerically resolved in the vertical and radial directions. Both vertically isothermal and thermally stratified accretion discs are considered. The waves are generated by means of resonant forcing and several forms of forcing are considered. Compress...

Recent observations of polar plumes in the southern solar coronal hole by the Extreme-Ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft show signatures of quasi-periodic compressional waves with periods of 10È15 minutes. The relative wave amplitude was found to increase with height in the plumes up to about 1.2 Using a one-dimensional linear wave equation for the magnetosonic R _...

Seismic exploration is one of the main geophysical methods to extract quantitative inferences about the Earth’s interior at different scales from the recording of seismic waves near the surface. Main applications are civil engineering for cavity detection and landslide characterization, site effect modelling for seismic hazard, CO2 sequestration and nuclearwaste storage, oil and gas exploration...

The Kelvin–Helmholtz (KH) instability of magnetohydrodynamic surface waves at the low latitude boundary layer is examined using both an eigenfrequency analysis and a time-dependent wave simulation. includes effects sheared flow Alfvén velocity gradient. When magnetosheath flows are perpendicular to ambient magnetic field direction, unstable KH that propagate obliquely direction occur when Mach ...

Mode-converted PS-waves can provide valuable information for anisotropic parameter estimation that cannot be obtained from compressional waves alone. In a previous paper, we developed an efficient tomographic methodology for 2D joint velocity analysis of PP and PS data from VTI (transversely isotropic with a vertical symmetry axis) media. The algorithm is designed to flatten image gathers of PP...

In recent years, ultrasonic methods have been developed that can be used to measure the mechanical stiffness of materials.1-5 In one such method, the velocity of a flexural plate wave, the lowest order antisymmetric Lamb mode, is measured as a function of frequency. Lamb waves arise from a coupling at the free boundaries between the shear waves and compressional waves in a plate structure.6 The...

The phenomenon of selective diffraction is extended to in-plane elastic waves and we design surface corrugated periodic laminates that incorporate crystal momentum transfer which, due the rich physics embedded within vector system, results in frequency, angle wave-type diffraction. resulting devices are grating couplers, with additional capabilities as compared analogous scalar electromagnetic ...

This study focused on geophysical and geomechanical analyses to arbitrate weak zones in Limestone of Gaj formation. Two boreholes were drilled used facilitate downhole seismic experiment down 30 meters depth. The method was supplied compressional waves velocities for inspection shallow subsurface properties evaluate local site condition. primary data P-waves are varying from 566 m/s 1225 (BH-1)...

Cloaking elastic waves has, in contrast to the cloaking of electromagnetic waves, remained a fundamental challenge: latter successfully uses invariance Maxwell’s equations, from which field transformational optics has emerged, whereas Navier equations are not invariant under coordinate transformations. Our aim is overcome this challenge, at least practical terms, and thereby unlock applications...