Movies of the breakup of viscous and viscoelastic drops in the high speed airstream behind a shock wave in a shock tube have been reported by Joseph, Belanger and Beavers [1999]. A Rayleigh-Taylor stability analysis for the initial breakup of a drop of Newtonian liquid was presented in that paper. The movies, which may be viewed at http://www.aem.umn.edu/ research/Aerodynamic_Breakup, show that...

Axisymmetric acoustic wave-modes propagating along buried water pipes have been investigated by the method of finite elements and experimentally. High precision dispersion relations are presented in this paper as a function of the geometry, the embedding material and the elastic modulus of the pipes. It is found that at low frequencies the fundamental axisymmetric acoustic mode of the water cyl...

In this paper, the propagation of time-harmonic torsional waves in composite elastic cylinders is investigated. An imperfect interface is considered where tractions are continuous across the interface and the displacement jump is proportional to the stress acting on the interface. A frequency equation is derived for the rod and dispersion curves of normalized frequency as a function of normaliz...

We report an experimental and theoretical study of single mode, guided wave propagation in plastic ribbons. Using cylindrical THz optics, we obtain excellent quasioptic coupling between freely propagating THz waves and a single TM 0 waveguide mode. Dispersive, low-loss propagation is observed within the experimental bandwidth of 0.1–3.5 THz for 2-cm-wide, high-density polyethylene ribbon wavegu...

Platelike structures, made of composites, are being increasingly used for fabricating aircraft wings and other aircraft substructures. Continuous monitoring of the health of these structures would aid the reliable operation of aircrafts. This paper considers the use of a Lamb wave based structural health monitoring SHM system to identify and locate defects in large multilayered composite plates...

A hollow, bottle-like microresonator (BLMR) was fabricated from a microcapillary with a nearly parabolic profile. From simulations at 1.55 μm the fundamental bottle mode is shown to be in the anomalous dispersion regime, while the conventional whispering gallery mode, confined to the center of the BLMR, is in the normal dispersion regime. Therefore, we have experimentally shown that, for a BLMR...

Analysis for the generalized thermoelastic Lamb waves, which propagates in anisotropic thin plates in generalized thermoelasticity, is presented employing normal mode expansion method. The displacement and temperature fields are expressed by a summation of the symmetric and antisymmetric thermoelastic modes in the surface thermal stresses and thermal gradient free orthotropic plate, therefore t...

The present investigation deals with the propagation of waves in the layer of an anisotropic fibre reinforced thermoelastic solid. Secular equations for symmetric and skew-symmetric modes of wave propagation in completely separate terms are derived. The amplitude of displacements and temperature distribution were also obtained. Finally, the numerical solution was carried out for Cobalt material...

[1] The vertical coherence of mantle structure is of importance for a range of dynamic issues including convective mass transport and the geochemical evolution of Earth. Here, we use seismic data to infer the most likely depth ranges of strong, global changes in the horizontal pattern of mantle heterogeneity. We apply our algorithm to a comprehensive set of measurements, including various shear...

Disorder of size (polydispersity) and mass of discrete elements or particles in randomly structured media (e.g., granular matter such as soil) has numerous effects on the materials’ sound propagation characteristics. The influence of disorder on energy and momentum transport, the sound wave speed and its low-pass frequency-filtering characteristics is the subject of this study. The goal is unde...