Biblio

This paper presents the synthesis and circuit transformations of acoustic wave filters based on a transversal arrangement of the individual resonators. This configuration allows for the synthesis of any filter response without detrimental of the limited value of the electro-acoustic coupling coefficient. The synthesis can be performed in the low-pass domain to be latter transformed into the band-pass domain. This latter step results in significant differences between the low-pass and the band-pass responses in wideband stringent filters. This work, after an initial synthesis in the low-pass domain, directly applies the pass-band circuit transformation achieving a more accurate synthesized network even for wideband filters.

By exploiting the simultaneous particle-conserving and particle-nonconserving phonon-photon interactions in an optomechanical array, we find a topologically protected edge state for phonons that can be parametrically amplified when all the bulk states remain stable.

There is some uncertainty as to the applicability or accuracy of current theories for wave propagation in sediments. Numerical modelling of acoustic data has long been recognized to be a powerful method of understanding of complicated wave propagation and interaction. In this paper, we used the coupled two-dimensional PSM-BEM program to simulate the process of acoustic wave propagation in the seafloor with distributed multi-scale random media. The effects of fluid flow between the pores and the grains with multi-scale distribution were considered. The results show that the coupled PSM-BEM program can be directly applied to both high and low frequency seafloor acoustics. A given porous frame with the pore space saturated with fluid can greatly increase the magnitude of acoustic anisotropy. acoustic wave velocity dispersion and attenuation are significant over a frequency range which spans at least two orders of magnitude.

The coupled thermohydroelastic processes of acoustic wave and heat propagation in weak viscous fluid and elastic bodies form the basis of dissipative acoustics. The problems of dissipative acoustics have many applications in engineering practice, in particular in the development of appropriate medical equipment. This paper presents mathematical models for time and frequency domain problems in terms of unknown displacements and temperatures in both the fluid and the elastic body. Formulated corresponding variational problems and constructed numerical schemes for their solution based on the Galerkin approximations. The method of proving the well-posedness of the considered variational problems is proposed.

Analysis of acoustic wave scattering by a finite flat impedance strip grating is presented. The associated two-dimensional (2-D) boundary-value problem is considered in the full-wave manner and cast to a set of coupled integral equations. Based on them, we build several mathematical models. The focus of research is on the acoustic plane wave scattering by a grating of narrow impedance strips that has explicit asymptotic solution.

Wireless transmission of power has been in research for over a century. Our project aims at transmitting electric power over a distance of room. Various methods using microwaves, lasers, inductive coupling, capacitive coupling and acoustic medium have been used. In our project, we are majorly focusing on acoustic method of transferring power. Previous attempts of transferring power using acoustic methods have employed the usage of ultrasonic sound. In our project, we are using infrasonic sound as a medium to transfer electrical power. For this purpose, we are using suitable transducers and converters to transmit electric power from the 220V AC power supply to a load over a considerable distance. This technology can be used to wirelessly charge various devices more effectively.