scholarly journals Interaction acoustic waves with a layered structure containing layer of bubbly liquid

2018 ◽  
Vol 148 ◽  
pp. 15006
Author(s):  
Damir Gubaidullin ◽  
Anatolii Nikiforov
Keyword(s):  
Acoustic Waves ◽  
Theoretical Study ◽  
Bubbly Liquid ◽  
Air Bubbles ◽  
Angle Of Incidence ◽  
Natural Oscillations ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Gel Layer ◽  
Transmission And Reflection

The results of a theoretical study of the effect of a bubble layer on the propagation of acoustic waves through a thin three-layered barrier at various angles of incidence are presented. The barrier consists of a layer of gel with polydisperse air bubbles bounded by layers of polycarbonate. It is shown that the presence of polydisperse air bubbles in the gel layer significantly changes the transmission and reflection of the acoustic signal when it interacts with such an obstacle for frequencies close to the resonant frequency of natural oscillations of the bubbles. The frequency range is identified where the angle of incidence has little effect on the reflection and transmission coefficients of acoustic waves.

scholarly journals Reflection and Transmission of Acoustic Waves through the Layer of Multifractional Bubbly Liquid

2018 ◽  
Vol 148 ◽  
pp. 15001
Author(s):  
Damir Anvarovich Gubaidullin ◽  
Ramil Nakipovich Gafiyatov
Keyword(s):  
Acoustic Waves ◽  
Wave Reflection ◽  
Water Model ◽  
Bubbly Liquid ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Multilayer Medium ◽  
Bubble Layer ◽  
The Mathematical Model ◽  
Theoretical Results

The mathematical model that determines reflection and transmission of acoustic wave through a medium containing multifractioanl bubbly liquid is presented. For the water-water with bubbles-water model the wave reflection and transmission coefficients are calculated. The influence of the bubble layer thickness on the investigated coefficients is shown. The theory compared with the experiment. It is shown that the theoretical results describe and explain well the available experimental data. It is revealed that the special dispersion and dissipative properties of the layer of bubbly liquid can significantly influence on the reflection and transmission of acoustic waves in multilayer medium

scholarly journals A proof that multiple waves propagate in ensemble-averaged particulate materials

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190344 ◽  
Author(s):  
Artur L. Gower ◽  
I. David Abrahams ◽  
William J. Parnell
Keyword(s):  
Acoustic Waves ◽  
Volume Fraction ◽  
Effective Medium Theory ◽  
Effective Medium ◽  
Inhomogeneous Material ◽  
Ensemble Averaging ◽  
Reflection And Transmission ◽  
Medium Theory ◽  
Transmission Coefficients ◽  
Cylindrical Inclusions

Effective medium theory aims to describe a complex inhomogeneous material in terms of a few important macroscopic parameters. To characterize wave propagation through an inhomogeneous material, the most crucial parameter is the effective wavenumber . For this reason, there are many published studies on how to calculate a single effective wavenumber. Here, we present a proof that there does not exist a unique effective wavenumber; instead, there are an infinite number of such (complex) wavenumbers. We show that in most parameter regimes only a small number of these effective wavenumbers make a significant contribution to the wave field. However, to accurately calculate the reflection and transmission coefficients, a large number of the (highly attenuating) effective waves is required. For clarity, we present results for scalar (acoustic) waves for a two-dimensional material filled (over a half-space) with randomly distributed circular cylindrical inclusions. We calculate the effective medium by ensemble averaging over all possible inhomogeneities. The proof is based on the application of the Wiener–Hopf technique and makes no assumption on the wavelength, particle boundary conditions/size or volume fraction. This technique provides a simple formula for the reflection coefficient, which can be explicitly evaluated for monopole scatterers. We compare results with an alternative numerical matching method.

THE SEISMIC WAVE ENERGY REFLECTED FROM VARIOUS TYPES OF STRATIFIED HORIZONS

Geophysics ◽  
1940 ◽  
Vol 5 (2) ◽  
pp. 149-155 ◽  
Author(s):  
M. Muskat ◽  
M. W. Meres
Keyword(s):  
Seismic Wave ◽  
Wave Energy ◽  
Incident Energy ◽  
Preceding Paper ◽  
Reflection And Transmission Coefficients ◽  
Angle Of Incidence ◽  
Reflection And Transmission ◽  
Transmission Coefficients

Two applications are made of the reflection and transmission coefficients reported in the preceding paper. These concern the effect of the angle of incidence upon the fraction of incident energy returning to the surface, and the effect of velocity stratification upon the energy return.

Scattering of surface waves obliquely incident on a fixed half immersed circular cylinder

1984 ◽  
Vol 96 (2) ◽  
pp. 359-369 ◽  
Author(s):  
B. N. Mandal ◽  
S. K. Goswami
Keyword(s):  
Integral Equation ◽  
Surface Water ◽  
Circular Cylinder ◽  
Water Waves ◽  
Wave Number ◽  
Angle Of Incidence ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Obliquely Incident ◽  
Surface Water Waves

AbstractThe problem of scattering of surface water waves obliquely incident on a fixed half immersed circular cylinder is solved approximately by reducing it to the solution of an integral equation and also by the method of multipoles. For different values of the angle of incidence and the wave number the reflection and transmission coefficients obtained by both methods are evaluated numerically and represented graphically to compare the results obtained by the respective methods.

Reflection and transmission from left-handed material structures using Lorentz and Drude medium models

2015 ◽  
Vol 23 (3) ◽  
Author(s):  
S.A. Taya ◽  
D.M. El−Amassi
Keyword(s):  
Slab Thickness ◽  
Band Pass Filter ◽  
Angle Of Incidence ◽  
Dielectric Slab ◽  
Electric Permittivity ◽  
Reflection And Transmission ◽  
Pass Filter ◽  
Transmission Coefficients ◽  
Left Handed ◽  
Band Pass

AbstractThe present article investigates theoretically the refection and transmission through a lossless dielectric slab embedded between two semi−infinite left−handed materials (LHMs) in which the electric permittivity and magnetic permeability are simultaneously negative. The LHM is assumed to be dispersive according to Lorentz as well as Drude medium model. The reflection and transmission coefficients are studied with the angle of incidence, frequency and slab thickness. The effect of the damping frequency is also investigated. It is found that the damping frequency has an insignificant effect on reflected, transmitted and loss powers. Band pass filter is one of the possible applications of the proposed structure.

Boundary conditions for a fluid‐saturated porous solid

Geophysics ◽  
1987 ◽  
Vol 52 (2) ◽  
pp. 174-178 ◽  
Author(s):  
Oscar M. Lovera
Keyword(s):  
Boundary Conditions ◽  
Total Energy ◽  
Elastic Medium ◽  
Contact Surface ◽  
Normal Component ◽  
Porous Solid ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Contact Surfaces ◽  
Transmission And Reflection

Using Biot’s theory, a set of boundary conditions is presented for wave transmission and reflection at the contact surface between an elastic medium (fluid or solid) and a fluid‐saturated porous solid (Biot medium). The analysis shows the continuity of the normal component of the density energy flux vectors across the contact surfaces, so that total energy is preserved. Energy reflection and transmission coefficients are computed for each kind of Biot wave.

scholarly journals The Scattering and Bound States of the Schrödinger Particle in Generalized Asymmetric Manning-Rosen Type Potential

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ahmet Taş ◽  
Soner Alpdoğan ◽  
Ali Havare
Keyword(s):  
Bound States ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Transmission And Reflection Coefficients ◽  
Scattering States ◽  
Different Types ◽  
Nonrelativistic Quantum Mechanics ◽  
Application Fields ◽  
Type Potential ◽  
Transmission And Reflection

We solve exactly one-dimensional Schrödinger equation for the generalized asymmetric Manning-Rosen (GAMAR) type potential containing the different types of physical potential that have many application fields in the nonrelativistic quantum mechanics and obtain the solutions in terms of the Gauss hypergeometric functions. Then we determine the solutions for scattering and bound states. By using these states we calculate the reflection and transmission coefficients for scattering states and achieve a correlation that gives the energy eigenvalues for the bound states. In addition to these, we show how the transmission and reflection coefficients depend on the parameters which describe shape of the GAMAR type potential and compare our results with the results obtained in earlier studies.

scholarly journals Reflection of acoustic waves from the boundary or layer of two-phase medium

2018 ◽  
Vol 148 ◽  
pp. 15005
Author(s):  
D.A. Gubaidullin ◽  
D.D. Gubaidullina ◽  
Yu.V. Fedorov
Keyword(s):  
Reflection Coefficient ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Finite Thickness ◽  
Low Frequency ◽  
Bubbly Liquid ◽  
Pure Liquid ◽  
Angle Of Incidence ◽  
Two Phase ◽  
Low Frequencies

The inclined incidence of the acoustic wave on a layer of gas-droplet mixture or bubbly liquid of finite thickness is theoretically investigated. In the case of the incidence of the low-frequency acoustic wave to interface between the pure gas and aerosol or to interface between pure liquid and bubbly liquid the basic laws of reflection and transmission of a wave are established. This circumstance allows us to evaluate the transmission and reflection coefficients, depending on the volume content of inclusions and the angle of incidence of the acoustic wave. In particular, for the interface between pure gas and aerosol analytical expressions of the critical angle of wave incidence at which reflection coefficient becomes zero are obtained, i.e. thus there is a complete passage of the acoustic wave through the interface. It is established that the increase of the angle of incidence of the acoustic wave on the boundary or layer of aerosol causes: first, either to increase or to decrease of the reflection coefficient at low frequencies, and second, to appearance of additional minima depending on the reflection coefficient from frequency of disturbances related to the difference of speed of sound and density of the medium.

Transmission and Reflection Coefficients for Damage Identification in 1D Elements

2009 ◽  
Vol 413-414 ◽  
pp. 95-100 ◽  
Author(s):  
Marek Krawczuk ◽  
Magdalena Palacz ◽  
Arkadiusz Zak ◽  
Wiesław M. Ostachowicz
Keyword(s):  
Damage Identification ◽  
Reflection And Transmission Coefficients ◽  
Reflection Coefficients ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Transmission And Reflection Coefficients ◽  
Structural Discontinuity ◽  
Spectral Finite Element ◽  
Processing Techniques ◽  
Transmission And Reflection

According to the latest research results presented in the literature changes in propagating waves are one of the most promising parameters for damage identification algorithms. Numerous publications describe methods of damage identification based on the analysis of signals reflected from damage. They also include complicated signal processing techniques. Such methods work well for damage localisation, but it is rather difficult to use them in order to estimate the size of damage. It is natural that propagating wave reflects from any structural discontinuity. The bigger the disturbance the bigger part of a propagating wave reflects from it. The amount of energy reflected and transmitted through any discontinuity can expressed as reflection and transmission coefficients. In the literature different application for these coefficients may be found – the most often cited application is connected with localising changes in the geometry of structures. Changes in the coefficients due to cross section variations in rods and beams or due to existence of stiffeners in plates are well documented. However there are no application of using the reflection and transmission coefficients for damage size identification. For this reason the analysis presented in this paper has been carried out. The article presents a method of damage identification in 1D elements based on the wave propagation phenomenon and changes in reflection and transmission coefficients. The changes in transmission and reflection coefficients for waves propagating in isotropic rods with different types of damage have been analysed. The rods have been modelled with the elementary, two and three mode theories or rods. For numerical modelling the Spectral Finite Element Method has been used. Several examples are given in the paper.

Dilatational waves at a microstretch solid/fluid interface

2016 ◽  
Vol 23 (20) ◽  
pp. 3448-3467 ◽  
Author(s):  
Dilbag Singh ◽  
Neela Rani ◽  
Sushil Kumar Tomar
Keyword(s):  
Half Space ◽  
Aluminum Matrix ◽  
Elastic Solid ◽  
Specific Model ◽  
Reflection And Transmission Coefficients ◽  
Angle Of Incidence ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Special Cases ◽  
Microstretch Fluid

The present work is concerned with the study of reflection and transmission phenomena of dilatational waves at a plane interface between a microstretch elastic solid half-space and a microstretch liquid half-space. Eringen's theory of micro-continuum materials has been employed for addressing the mathematical analysis. Reflection and transmission coefficients, corresponding to various reflected and transmitted waves, have been obtained when a plane dilatational wave strikes obliquely at the interface after propagating through the solid half-space. It is found that the reflection and transmission coefficients are functions of the angle of incidence, the frequency of the incident wave and the elastic properties of the half-spaces. Numerical calculations have been carried out for a specific model by taking an aluminum matrix with randomly distributed epoxy spheres as the microstretch solid medium, while the microstretch fluid is taken arbitrarily with suitably chosen elastic parameters. The computed results obtained have been depicted graphically. The results of earlier studies have been deduced from the present formulation as special cases.

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