Investigation of the energy flow direction of elastic waves in crystals by acoustoelectric probe

1972 ◽  
Vol 14 (1) ◽  
pp. 339-346 ◽  
Author(s):  
A. I. Morozov ◽  
M. A. Zemlyanitsin ◽  
V. I. Anisimkin
1974 ◽  
Vol 24 (1) ◽  
pp. 381-381 ◽  
Author(s):  
A. I. Morozov ◽  
M. A. Zemlyanitsin ◽  
V. I. Anisimkin

1961 ◽  
Vol 39 (1) ◽  
pp. 65-80 ◽  
Author(s):  
G. W. Farnell

In non-isotropic single crystals the normals to the wavefronts of elastic waves are not colinear with the vectors representing either the energy flow or the particle displacement. Calculations have been carried out on the propagation characteristics of sound waves in two particular trigonal crystals, α-quartz and sapphire.The development of the eigenvalue equation for the velocity and the formulae for the components of the displacement and energy-flow vectors are summarized. The assumption that the wave has a plane wavefront normal to a given direction leads to three solutions, one representing a quasi-longitudinal wave and the other two representing quasi-transverse waves. The velocities of propagation, directions of displacement, and directions of energy flow for the three waves have been calculated for many orientations of the wave normal. Detailed results for propagation near one of the pure-mode axes are presented.


2010 ◽  
Vol 168-169 ◽  
pp. 173-176
Author(s):  
S.A. Migachev ◽  
M.F. Sadykov ◽  
M.M. Shakirzyanov ◽  
D.A. Ivanov

In a trigonal easy-plane -Fe2O3 antiferromagnet magnetic-field-dependent conic refraction due to the renormalization of the coefficients of elasticity effective magnetoelastic interaction is experimentally found in addition to the conventional internal conic refraction of the transverse elastic waves propagating along the trigonal C3 axis. It is shown that the deflection angle () of the energy flow from the C3 axis upon the internal conic refraction does not depend on the value of the magnetic field applied in the basis plane (HC3) and is a constant value determined by the correlation of the C14 and C44 coefficients of elasticity. The deflection angle of the energy flow upon the antiferromagnetic conic refraction () increases with increase in the field and tends to the  value at large H values. The obtained results agree well with the theory of this phenomenon in antiferromagnets and support its conclusions.


Author(s):  
T. Lafont ◽  
N. Totaro ◽  
A. Le Bot

This paper is a discussion of the hypothesis of weak coupling in statistical energy analysis (SEA). The examples of coupled oscillators and statistical ensembles of coupled plates excited by broadband random forces are discussed. In each case, a reference calculation is compared with the SEA calculation. First, it is shown that the main SEA relation, the coupling power proportionality, is always valid for two oscillators irrespective of the coupling strength. But the case of three subsystems, consisting of oscillators or ensembles of plates, indicates that the coupling power proportionality fails when the coupling is strong. Strong coupling leads to non-zero indirect coupling loss factors and, sometimes, even to a reversal of the energy flow direction from low to high vibrational temperature.


2021 ◽  
Vol 2127 (1) ◽  
pp. 012039
Author(s):  
N V Polikarpova ◽  
I K Chizh

Abstract The methods of acousto-optics provide multiple techniques for controlling optical beam. The technical parameters of corresponding acousto-optic devices are largely determined by the efficiency of acoustic waves generation. In present work we examine the features of elastic waves generation in materials used in acousto-optics. In most of practical applications the elastic wave generation process is implemented through the refraction of elastic waves at the boundary between two anisotropic media. We present a detailed study of the refraction of elastic waves in strongly anisotropic media. We report new refractive effects such as “extraordinary” refraction. In the latter case the change in the direction of the incident acoustic wave does not influence the direction of the energy flow propagation for refracted elastic waves. The configuration of an acousto-optic device using the geometry of unusual refraction in an anisotropic medium is discussed.


2009 ◽  
Vol 36 (7) ◽  
pp. 1245-1252 ◽  
Author(s):  
N. Rajaratnam ◽  
M. A.F. Sadeque ◽  
C. Katopodis

A simple method has been developed to predict the flow division at the louver, based on the experimental finding of Shepherd et al. (2007) that the specific energy of the flow through a diversion structure housing a louver system is approximately constant. Flow through louver slot is expressed using a consolidated contraction coefficient to account for the lumped effect of flow contraction between the louver slats and the approximations of the proposed theoretical model (e.g., constant specific energy, flow direction through the louver slots). A relationship is developed for the consolidated coefficient from the simulation of experimental results obtained from Shepherd et al. (2007). It is observed from the simulation results that the consolidated contraction coefficient is best correlated with the relative width of the bypass. Finally, the use of this simple method is demonstrated using a set of numerical experiments within the range of experimental conditions of the louver system.


Geophysics ◽  
1984 ◽  
Vol 49 (9) ◽  
pp. 1562-1562
Author(s):  
J. D. Laski

Investigating waves for sedimentary series, Morlet et al. start from basic formulas for elastic waves. I have compared formulas used by Morlet et al. for: (a) compressional velocity of elastic waves, (b) stress‐strain relationship, and (c) energy flow vector (Poynting’s vector), with corresponding formulas in Koehler and Taner (1977). The results follow.


Sign in / Sign up

Export Citation Format

Share Document