the velocity data of seismic waves in a region has an important role in locating occurred events. information such as velocity ratio of vp/vs and velocity curves for pg, pn, sg, and sn phases directly affect the locating results. it is well known that the vp/vs ratio can be used to predict lithology, and that s-waves are sensitive to microcracks aligned by the present day stress field. also, th...

The phenomenon of coherent wave trapping and restoration is demonstrated experimentally in a magnonic crystal. Unlike the conventional scheme used in photonics, the trapping occurs not due to the deceleration of the incident wave when it enters the periodic structure but due to excitation of the quasinormal modes of the artificial crystal. This excitation occurs at the group velocity minima of ...

Free gas bubbles in water with radii between 7 and 55 microm subjected to a shock wave exhibit a liquid jetting phenomenon with the jet pointing in the direction of the propagating shock wave. With increasing bubble radius, the length of the jet tip increases and a lower estimate of the averaged jet velocity increases linearly from 20 to 150 m/s. At a later stage, the jet breaks up and releases...

Void detection is challenging due to the complexity of near-surface materials and the limited resolution of geophysical methods. Although multichannel, high-frequency, surfacewave techniques can provide reliable S-wave velocities in different geological settings, they are not suitable for detecting voids directly based on anomalies of the S-wave velocity because of limitations on the resolution...

designing and manufacturing the multiple jets simulator and experimental investigation of the multiple jets in crossflow at low velocity ratios have been studied together with design and build a low-speed wind tunnel. a specific rake is used to determine the flow field pressure and changes in static pressure measured by pressure taps in the near field of the jets. there are generally three regi...

The stress wave propagation in a generalized thermoelastic polygonal plate of inner and outer cross sections is studied using the Fourier expansion collocation method. The wave equation of motion based on two-dimensional theory of elasticity is applied under the plane strain assumption of generalized thermoelastic plate of polygonal shape, composed of homogeneous isotropic material.  The freque...

Although Love waves are widely analyzed in earthquake seismology, there is much less attention on utilizing Love waves than Rayleigh waves by the near-surface community. Unlike incident P and Sv waves, a plane SH wave for a series of horizontal layers refracts and reflects only SH waves, which makes the shallow SH-wave refraction method more popular to define shear (S)-wave velocity in nearsurf...

We expand our pervious numerical study of the properties of the stellar velocity distribution within the disk of a twoarmed spiral galaxy by considering spiral stellar density waves with different global Fourier amplitudes, C2. We confirm our previous conclusion that the ratio σ1 : σ2 of smallest versus largest principal axes of the stellar velocity ellipsoid becomes abnormally small near the o...

contrary to the long period ground motions that can be predicted and estimated, high frequency ground motions have random character and behave stochastically. stochastic modeling methods are usually used for the modeling of high frequency ground motions where there are not strong ground motion records. stochastic methods are of two kinds: in the first one, the seismic source is considered as a ...

We report on further developments of a hybrid numerical model to simulate wave-induced sediment transport. A 2D numerical wavetank (NWT) based on fully nonlinear potential flow (FNPF) equations is used to simulate fully nonlinear wave generation and propagation. A 3D Navier-Stokes model with large eddy simulation (LES) is coupled to the NWT to simulate complex turbulent flows near the ocean bot...