Propagation and interaction with obstructions of acoustic waves in vapor-gas-liquid media

2012 ◽  
Vol 9 (1) ◽  
pp. 121-124
Author(s):  
A.A. Nikiforov
Keyword(s):  
Acoustic Waves ◽  
Rigid Wall ◽  
Bubble Medium ◽  
Liquid Media ◽  
Reflection And Transmission ◽  
Initial Wave ◽  
The Waves ◽  
Analytical Expressions ◽  
Transmission And Reflection

Transmission and reflection of acoustic waves from a layer of a bubble medium into a liquid is theoretically studied, with subsequent reflection of the waves that arise from the rigid wall. The amplitudes of the emerging waves are determined through the amplitude of the initial wave, analytical expressions are obtained for the coefficients of reflection and transmission of waves across the interfaces.

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.

Acoustic tunnelling

1978 ◽  
Vol 81 (1-2) ◽  
pp. 1-21 ◽  
Author(s):  
D. S. Jones
Keyword(s):  
Circular Cylinder ◽  
Acoustic Waves ◽  
Total Internal Reflection ◽  
Internal Reflection ◽  
Reflection And Transmission ◽  
Curved Interface ◽  
Transmission And Reflection

SynopsisGeneral formulae are obtained for the reflection and transmission of harmonic acoustic waves by a curved interface between two media when the frequency is high. In addition to refracted rays there turn up tunnelling rays, if the surface is concave to the source, which are emitted from an evanescent region when the phenomenon of total internal reflection would be anticipated. Uniformly valid formulae dealing with the transition from refraction to tunnelling in both transmission and reflection are derived.The theory is applied to the circular cylinder and to the top-hat circular jet. In the latter case it is suggested that radiation may tend to be more significant at inclinations of 50°-65° (downstream) and 25°-40° (upstream) to the axis of the cylinder. The augmentation due to tunnelling rays in propagation upstream is mentioned.

Interaction of an acoustic wave with a multilayer medium containing a bubble liquid layer

2019 ◽  
Vol 14 (4) ◽  
pp. 233-242
Author(s):  
U.O. Agisheva ◽  
M.N. Galimzyanov
Keyword(s):  
Acoustic Waves ◽  
Wave Dispersion ◽  
Point Of View ◽  
Bubble Medium ◽  
Existence Of A Solution ◽  
Reflection And Transmission ◽  
Bubble Liquid ◽  
Carrier Liquid ◽  
Transmitted Waves ◽  
Layer Medium

Discrete-layered media are interesting to research since properties of each layer can significantly differ from near by ones and this can be used in technological processes. The presence of a small number of bubbles significantly increases the compressibility of the medium while the density of the bubble medium remains close to the density of the carrier liquid. From the applied point of view it is interesting that the energy of the incident wave can be completely absorbed by combining of layer properties (length, volume content of the dispersed phase, etc.). In this work, based on the equations of mechanics of dispersed media, we consider the reflection and propagation of acoustic waves passing at right angles through a three-layer medium in a pipeline containing a layer of bubble fluid. From the condition for the existence of a solution in the form of a decaying traveling wave, dispersion relations are written for each of the possible layers. Based on them, the dependences of the amplitude of the incident and transmitted waves on the propagation velocity of the pulse are analytically derived. The coefficients of reflection and transmission through the interface are obtained both in the general case and in particular cases for each layer. These ratios make it possible to calculate the possible consequences of a wave action on the considered media in the event of emergencies at work and to prevent them.

Parametric excitation of magnetoacoustic waves by a pump magnetic field in a high-β plasma

1977 ◽  
Vol 17 (1) ◽  
pp. 93-103 ◽  
Author(s):  
N. F. Cramer
Keyword(s):  
Magnetic Field ◽  
Parametric Excitation ◽  
Acoustic Waves ◽  
Magnetic Pressure ◽  
Gas Pressure ◽  
Alfven Wave ◽  
Fast Wave ◽  
Magnetoacoustic Waves ◽  
Background Magnetic Field ◽  
The Waves

The parametric excitation of slow, intermediate (Alfvén) and fast magneto-acoustic waves by a modulated spatially non-uniform magnetic field in a plasma with a finite ratio of gas pressure to magnetic pressure is considered. The waves are excited in pairs, either pairs of the same mode, or a pair of different modes. The growth rates of the instabilities are calculated and compared with the known result for the Alfvén wave in a zero gas pressure plasma. The only waves that are found not to be excited are the slow plus fast wave pair, and the intermediate plus slow or fast wave pair (unless the waves have a component of propagation direction perpendicular to both the background magnetic field and the direction of non-uniformity of the field).

scholarly journals ANALYSIS OF DISPERSION ERRORS IN ACOUSTIC WAVE SIMULATIONS

2006 ◽  
Vol 5 (1) ◽  
pp. 62
Author(s):  
R. A. C. Germanos ◽  
L. F. De Souza
Keyword(s):  
Acoustic Wave ◽  
Fourth Order ◽  
Finite Differences ◽  
Acoustic Waves ◽  
Time Integration ◽  
Compact Scheme ◽  
High Order Accuracy ◽  
Discretization Schemes ◽  
Analysis Of Dispersion ◽  
The Waves

The governing equations of the acoustic problem are the compressible Euler equations. The discretization of these equations has to ensure that the acoustic waves are transported with non-dispersive and non-dissipative characteristics. In the present study numerical simulations of a standing acoustic wave are performed. Four different space discretization schemes are tested, namely, a second order finite-differences, a fourth order finitedifferences, a fourth order finite-differences compact scheme and a sixth order finite-differences compact scheme. The time integration is done with a fourth order Runge-Kutta scheme. The results obtained are compared with linearized analytical solutions. The influence of the dispersion on the simulation of a standing wave is analyzed. The results confirm that high order accuracy schemes can be more efficient for simulation of acoustic waves, especially the waves with high frequency.

Stability of linear shear flows in shallow water

1995 ◽  
Vol 303 ◽  
pp. 203-214 ◽  
Author(s):  
Charles Knessl ◽  
Joseph B. Keller
Keyword(s):  
Shallow Water ◽  
Shear Flows ◽  
Special Functions ◽  
Rigid Wall ◽  
Eigenvalue Equation ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Linear Shear ◽  
The Stability ◽  
Rigid Walls

The stability or instability of various linear shear flows in shallow water is considered. The linearized equations for waves on the surface of each flow are solved exactly in terms of known special functions. For unbounded shear flows, the exact reflection and transmission coefficients R and T for waves incident on the flow, are found. They are shown to satisfy the relation |R|2= 1+ |T|2, which proves that over reflection occurs at all wavenumbers. For flow bounded by a rigid wall, R is found. The poles of R yield the eigenvalue equation from which the unstable mides can be found. For flow in a channel, with two rigid walls, the eigenvalue equation for the modes is obtained. The results are compared with previous numerical results.

Plasma cavity formation caused by ion acoustic waves and nonlinear modulation of trapped waves

1999 ◽  
Vol 61 (3) ◽  
pp. 489-505
Author(s):  
T. HONZAWA ◽  
S. WATANABE ◽  
Y. SAITOU
Keyword(s):  
Acoustic Waves ◽  
Early Stage ◽  
Cavity Formation ◽  
Pressure Gradients ◽  
Trapped Waves ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Nonlinear Modulation ◽  
Ion Waves ◽  
The Waves

Externally amplitude-modulated ion acoustic waves with high frequencies of 200–320 kHz are experimentally shown to form plasma cavities and to be trapped in them at an early stage. Thereafter, the trapped waves are observed to suffer nonlinear modulation and create new lower-frequency waves with average frequencies as low as 20–40 kHz within the cavities. As a result, the externally excited high-frequency ion acoustic waves are found to be nonlinearly converted into lower-frequency ion waves in the cavities. Finally, the pressure gradients of the waves effective in cavity formation and nonlinear modulation of the trapped waves are discussed.

Coupled fields in inhomogeneous warm plasmas with static pressure gradients. I

1972 ◽  
Vol 72 (2) ◽  
pp. 285-297
Author(s):  
R. Burman
Keyword(s):  
Pressure Gradient ◽  
Acoustic Waves ◽  
Wave Equations ◽  
Static Pressure ◽  
Pressure Gradients ◽  
Coupling Region ◽  
Electron Plasmas ◽  
Coupled Wave Equations ◽  
Electron Acoustic ◽  
The Waves

Abstract.This paper deals with small amplitude waves in inhomogeneous warm electron plasmas. The waves are coupled electromagnetic and electron-acoustic waves, and are described by Maxwell's equations together with single-fluid hydrodynamical equations. Here, previous work is generalized by including the effect of a static pressure gradient. Coupled wave equations are obtained and specialized to the case of a planar stratified plasma. Then, as a preliminary to a treatment of wave coupling, the behaviour of the solutions of the uncoupled wave equations in a coupling region is investigated. The static pressure gradient complicates the behaviour of the uncoupled field components; singularities occur at two points which coalesce as the static pressure gradient is allowed to tend to zero.

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

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