Abstract Advanced research into non-destructive control of industrial pipeworks provides several acoustical methods for inspection of their structural integrity. Applying guided waves is one possible solution to detect and identify different flaws. Many studies have shown the importance of complex waves describing the interaction phenomena at the vicinity of the defects, modeled as geometrical ...

We present a time domain analysis and comparison of spatial discretization artifacts in near-field compensated higher order Ambisonics and wave field synthesis. Simulations of both methods on the same circular loudspeaker array are investigated and the results are interpreted in terms of fundamental psycho-acoustical properties of the human auditory system, most notably the precedence effect. I...

The theory of wave propagation and scattering in cracked media is applied to study the wave attenuations in an isotropic solid medium containing perfectly aligned penny-shaped microcracks. The unit normals of all cracks are assumed parallel to a given direction. The wave scattering model is formulated using an anisotropic Green’s dyadic approach. Explicit expressions are derived for attenuation...

A focused acoustic standing wave creates a Hookean potential well for small sphere and can levitate it stably against gravity. Exposing the trapped to second transverse traveling sound imposes an additional acoustical force that drives away from its mechanical equilibrium. The driving is shaped by interference between trapping driving. If, furthermore, detuned wave, oscillates at difference fre...

A preliminary study is presented that investigates processing of microphone array signals for multi-channel recording applications. Generalised, perceptually and acoustically based approaches are taken, where a spaced array of M microphones is mapped to an array of L loudspeakers. The principal objective is to establish transformation matrices that integrate both microphone and loudspeaker arra...

Self-similar deformation of three-wave stimulated Brillouin scattering (SBS) dissipative structures (“Brillouin quasi-solitons”) yields superluminous behaviors. The authors discuss the relevancy of the various velocities involved in the nonlinear propagation of such complex structures, both in the ideal semi-infinite case and in a real-world Brillouin fiber ring laser experiment. Optical and ac...

In a time of heightened environmental concerns and increased importance on efficiency, thermoacoustic standing waves and oscillations provide a possible solution to many contemporary problems. Elementary standing wave theory is discussed, as well as the connection between thermodynamics and acoustical oscillations. Additionally, the benefits of Sondhauss oscillations and devices for their produ...

Measurements of the spatial distribution of the time-averaged second-order pressure in a plane standing wave in atmospheric air are reported. Several measurement pitfalls are identified, and solutions are described. These include accounting for slight nonlinearity of the piezoresistive transducer and careful mounting of the transducer. Streaming causes extra complication when a capillary-connec...

Two semi-infinite elastic plates are joined along a line forming a wedge structure with unilateral fluid loading in the outer sector of the two plates. The structure is modeled using thin plate theory, allowing freely propagating flexural and longitudinal waves. The junction is mechanically connected with an applied force and moment acting there to simulate a possible internal connection. The g...