scholarly journals On wave propagation in a random micropolar generalized thermoelastic medium

2017 ◽  
Vol 38 (2) ◽  
pp. 21-60 ◽  
Author(s):  
Manindra Mitra ◽  
Rabindra Kumar Bhattacharyya
Keyword(s):  
Wave Propagation ◽  
Elastic Medium ◽  
Correlation Functions ◽  
Perturbation Technique ◽  
Random Medium ◽  
Phase Speed ◽  
Attenuation Coefficients ◽  
Different Types ◽  
Smooth Perturbation ◽  
High Frequency Waves

AbstractThis paper endeavours to study aspects of wave propagation in a random generalized-thermal micropolar elastic medium. The smooth perturbation technique conformable to stochastic differential equations has been employed. Six different types of waves propagate in the random medium. The dispersion equations have been derived. The effects due to random variations of micropolar elastic and generalized thermal parameters have been computed. Randomness causes change of phase speed and attenuation of waves. Attenuation coefficients for high frequency waves have been computed. Second moment properties have been briefly discussed with application to wave propagation in the random micropolar elastic medium. Integrals involving correlation functions have been transformed to radial forms. A special type of generalized thermo-mechanical auto-correlation functions has been used to approximately compute effects of random variations of parameters. Uncoupled problem has been briefly outlined.

Transverse surface waves in magneto-elasticity

1966 ◽  
Vol 62 (3) ◽  
pp. 541-545 ◽  
Author(s):  
C. M. Purushothama
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Surface Waves ◽  
Elastic Medium ◽  
Uniform Magnetic Field ◽  
Shear Waves ◽  
Plane Shear ◽  
Electrically Conducting ◽  
Velocity Of Propagation

AbstractIt has been shown that uncoupled surface waves of SH type can be propagated without any dispersion in an electrically conducting semi-infinite elastic medium provided a uniform magnetic field acts non-aligned to the direction of wave propagation. In general, the velocity of propagation will be slightly greater than that of plane shear waves in the medium.

scholarly journals LOW-HYBRID WAVE PROPAGATION AFFECTED BY A RANDOM MEDIUM LAYER

1988 ◽  
Vol 37 (10) ◽  
pp. 1678
Author(s):  
PAN CHUAN-HONG ◽  
QIU XIAO-MING
Keyword(s):  
Wave Propagation ◽  
Random Medium ◽  
Hybrid Wave ◽  
Medium Layer

scholarly journals Inferring the chromospheric magnetic topology through waves

2007 ◽  
Vol 3 (S247) ◽  
pp. 78-81
Author(s):  
S. S. Hasan ◽  
O. Steiner ◽  
A. van Ballegooijen
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Energy Density ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Phase Speed ◽  
Time Correlation ◽  
Propagation Time ◽  
Fast Mode ◽  
The Magnetic Field

AbstractThe aim of this work is to examine the hypothesis that the wave propagation time in the solar atmosphere can be used to infer the magnetic topography in the chromosphere as suggested by Finsterle et al. (2004). We do this by using an extension of our earlier 2-D MHD work on the interaction of acoustic waves with a flux sheet. It is well known that these waves undergo mode transformation due to the presence of a magnetic field which is particularly effective at the surface of equipartition between the magnetic and thermal energy density, the β = 1 surface. This transformation depends sensitively on the angle between the wave vector and the local field direction. At the β = 1 interface, the wave that enters the flux sheet, (essentially the fast mode) has a higher phase speed than the incident acoustic wave. A time correlation between wave motions in the non-magnetic and magnetic regions could therefore provide a powerful diagnostic for mapping the magnetic field in the chromospheric network.

scholarly journals Strongly Intensive Observables in the Model with String Fusion

Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 15 ◽  
Author(s):  
Vladimir Vechernin ◽  
Evgeny Andronov
Keyword(s):  
Correlation Functions ◽  
Opposite Sign ◽  
Pair Correlation ◽  
Balance Function ◽  
Pair Correlation Functions ◽  
Particle Correlation ◽  
Collision Centrality ◽  
Different Types ◽  
Charge Sign

We calculate the strongly intensive observables for multiplicities in two rapidity windows in the model with independent identical strings taking into account the charge sign of particles. We express the observables through the string pair correlation functions describing the correlations between the same and opposite sign particles produced in a string decay. We extract these charge-wise string two-particle correlation functions from the ALICE data on the forward-backward correlations and the balance function. Using them we predict the behavior of the charge-wise strongly intensive observables in the model with independent identical strings. We also show that the observable between multiplicities in two acceptance windows separated in rapidity, which is a strongly intensive in the case with independent identical strings, loses this property, when we take into account string fusion effects and a formation of strings of a few different types takes place in a collision. We predict the changes in the behaviour of this observable with energy and collision centrality, arising due to the string fusion phenomena.

Wave Propagation and Parametric Instability in Materials Reinforced by Fibers With Periodically Varying Directions

1975 ◽  
Vol 42 (4) ◽  
pp. 825-831 ◽  
Author(s):  
M. Schoenberg ◽  
Y. Weitsman
Keyword(s):  
Composite Material ◽  
Wave Propagation ◽  
Elastic Medium ◽  
Parametric Instability ◽  
Transversely Isotropic ◽  
Harmonic Waves ◽  
Fiber Reinforced ◽  
Frequency Bands ◽  
Structural Periodicity ◽  
Dominant Direction

This paper concerns the propagation of plane harmonic waves in an infinite fiber-reinforced elastic medium. The composite material is represented by an equivalent homogeneous transversely isotropic matter whose preferred directions coincide with the orientations of the fibers. The fibers are assumed to wobble periodically about a dominant direction, all fibers being parallel to each other. This wobbliness endows the material with a structural periodicity which generates dispersion at all frequencies and instability for various frequency bands. The zones of instability are analyzed in some detail.

Torsional Wave Propagation in a Circular Cylinder with a Periodically Corrugated Outer Surface

1999 ◽  
Vol 121 (4) ◽  
pp. 501-505 ◽  
Author(s):  
J. O. Kim
Keyword(s):  
Circular Cylinder ◽  
Outer Surface ◽  
Elastic Waves ◽  
Wave Speed ◽  
Perturbation Technique ◽  
Phase Speed ◽  
Outer Radius ◽  
Axial Coordinate ◽  
Speed Reduction ◽  
Smooth Cylinder

The paper describes a theoretical study on the speed of torsional elastic waves propagating in a circular cylinder whose outer radius varies periodically as a harmonic function of the axial coordinate. An approximate solution for the phase speed was obtained by using the perturbation technique for sinusoidal modulation of a small amplitude. This shows that the wave speed in the cylinder with a corrugated outer surface is less than that in a smooth cylinder by the square of the amplitude of the surface perturbation. This theoretical prediction reasonably agrees with an experimental observation reported earlier. It is also shown that the wave speed reduction due to the surface corrugation becomes larger for a thinner cylinder and for a bigger density of corrugation.

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