Reflection of plane waves in thermoelastic medium with double porosity

2016 ◽  
Vol 12 (4) ◽  
pp. 748-778 ◽  
Author(s):  
Rajneesh Kumar ◽  
Richa Vohra ◽  
M.G. Gorla
Keyword(s):  
Relaxation Time ◽  
Earthquake Engineering ◽  
Plane Waves ◽  
Practical Importance ◽  
Double Porosity ◽  
Angle Of Incidence ◽  
Amplitude Ratios ◽  
Thermoelastic Medium ◽  
Content Type ◽  
The Earth

Purpose The purpose of this paper is to study the reflection of plane waves in thermoelastic medium with double porosity structure. Design/methodology/approach A two-dimensional model is considered of an isotropic thermoelastic half-space with double porosity. Thermoelasticity with one relaxation time given by Lord and Shulman (1967) has been used to study the problem. It is found that there exists four coupled longitudinal waves, namely, longitudinal wave (P), longitudinal thermal wave (T), longitudinal volume fractional wave corresponding to pores (PVI) and longitudinal volume fractional wave corresponding to fissures (PVII), in addition to an uncoupled transverse wave (SV). Findings The formulae for amplitude ratios of various reflected waves are obtained in closed form. It is found that these amplitude ratios are functions of angle of incidence. Effect of porosity and thermal relaxation time is shown graphically on the amplitude ratios with angle of incidence for a particular model. Originality/value Reflection of plane waves is of great practical importance. There are many organic and inorganic deposits beneath the earth surface. Wave propagation is the simplest and most economical technique to detect these. The model discussed in the present paper can provide useful information for experimental researchers working in the field of geophysics and earthquake engineering, along with seismologist working in the field of mining tremors and drilling into the crust of the earth.

Wave propagation in an initially stressed rotating thermo-diffusive medium with two-temperature and micro-concentrations

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Devender Sheoran ◽  
Ramesh Kumar ◽  
Sunil Kumar ◽  
Kapil Kumar Kalkal
Keyword(s):  
Plane Waves ◽  
Generalized Thermoelasticity ◽  
Angle Of Incidence ◽  
Amplitude Ratios ◽  
Conservation Of Energy ◽  
Content Type ◽  
Reflected Waves ◽  
Diffusive Medium ◽  
Energy Ratios ◽  
Two Temperature

Purpose The purpose of this paper is to study the reflection of plane waves in an initially stressed rotating thermoelastic diffusive medium with micro-concentrations and two-temperature. Design/methodology/approach A two-dimensional model of generalized thermoelasticity is considered. The governing equations are transformed into the non-dimensional forms using the dimensionless variables. Then, potential functions are introduced for the decoupling of the waves. Further, appropriate boundary conditions are assumed to completely solve the problem. Finally, numerical computations are performed using MATLAB. Findings The problem is solved analytically and it is found that there exist five coupled waves in addition to an independent micro-concentration wave in the considered medium. The amplitude ratios and energy ratios of these reflected waves have also been computed numerically for a specific material. Originality/value The modulus values of amplitude ratios are presented graphically to exhibit the effects of angular velocity, initial stress, two-temperature, diffusion and micro-concentration parameters. The expressions of energy ratios obtained in explicit form are also depicted graphically as functions of angle of incidence. The law of conservation of energy at the free surface during reflection phenomenon is also verified.

scholarly journals Influence of Diffusion and Impedence Parameters on Wave Propagation in Thermoelastic Medium

2021 ◽  
Vol 26 (4) ◽  
pp. 99-112
Author(s):  
Sachin Kaushal ◽  
Rajneesh Kumar ◽  
Kulwinder Parmar
Keyword(s):  
Plane Waves ◽  
Angle Of Incidence ◽  
Amplitude Ratios ◽  
Thermoelastic Medium ◽  
Impedance Boundary ◽  
Reflected Waves ◽  
Diffusion Relaxation ◽  
Impedance Parameters ◽  
The Impact ◽  
Coupled Theory

Abstract The aim of the present paper is to study the impact of diffusion and impedance parameters on the propagation of plane waves in a thermoelastic medium for Green and Lindsay theory (G-L) and the Coupled theory (C-T) of thermoelasticity. Results are demonstrated for impedance boundary conditions and the amplitude ratios of various reflected waves against the angle of incidence are calculated numerically. The characteristics of diffusion, relaxation time and impedence parameter on amplitude ratios have been depicted graphically. Some cases of interest are also derived from the present investigation.

Laser pulses and rotation effects with the temperature-dependent properties in micropolar thermoelastic solids with microtemperatures

2019 ◽  
Vol 15 (2) ◽  
pp. 418-436 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
Ramadan S. Tantawi ◽  
Mohamed I.M. Hilal
Keyword(s):  
Earthquake Engineering ◽  
Human Body ◽  
Design Methodology ◽  
Laser Pulses ◽  
Temperature Dependent ◽  
Thermoelastic Medium ◽  
Content Type ◽  
Thermoelastic Solid ◽  
Temperature Dependent Properties ◽  
Physical Quantities

PurposeThe purpose of this paper is to report effect of rotation of micropolar thermoelastic solid with microtemperatures heated by laser pulses. The problem was solved analytically to obtain the expressions of the physical quantities.Design/methodology/approachThe analytical method used was the normal mode.FindingsNumerical results for the physical quantities were presented graphically and the results were analyzed. The comparisons were established in variant cases of the effects used and then shown graphically.Originality/valueIn the present work, the authors shall discuss the effect of rotation and temperature-dependent properties with the laser pulses in the micropolar thermoelastic medium with microtemperatures. This problem is very important in more empirical branches such as the human body and earthquake engineering.

scholarly journals Reflection at Free Surface in Micropolar Thermoelastic Solid with two Temperatures

2013 ◽  
Vol 18 (1) ◽  
pp. 217-234 ◽  
Author(s):  
K. Sharma
Keyword(s):  
Half Space ◽  
Plane Surface ◽  
Plane Waves ◽  
Relaxation Times ◽  
Specific Model ◽  
Angle Of Incidence ◽  
Amplitude Ratios ◽  
Two Temperatures ◽  
Generalized Thermoelastic ◽  
Thermoelastic Solid

The present investigation is concerned with the effect of two temperatures on reflection coefficients in a micropolar thermoelastic solid half space. With two relaxation times, reflection of plane waves impinging obliquely at a plane interface of the micropolar generalized thermoelastic solid half space with two temperatures is investigated. The incident wave is assumed to be striking at the plane surface after propagating through the micropolar generalized thermoelastic solid with two temperatures. Amplitude ratios of the various reflected waves are obtained in closed form and it is found that these are functions of angle of incidence, frequency and are affected by the elastic properties of the media. The effect of two temperatures is shown on these amplitude ratios for a specific model.

scholarly journals Effect of Two Temperatures on Reflection Coefficient in Micropolar Thermoelastic with and without Energy Dissipation Media

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Rajneesh Kumar ◽  
K. D. Sharma ◽  
S. K. Garg
Keyword(s):  
Energy Dissipation ◽  
Temperature Effects ◽  
Plane Waves ◽  
Angle Of Incidence ◽  
Amplitude Ratios ◽  
Reflected Waves ◽  
Two Temperatures ◽  
Thermally Conducting ◽  
Without Energy Dissipation ◽  
Two Temperature

The reflection of plane waves at the free surface of thermally conducting micropolar elastic medium with two temperatures is studied. The theory of thermoelasticity with and without energy dissipation is used to investigate the problem. The expressions for amplitudes ratios of reflected waves at different angles of incident wave are obtained. Dissipation of energy and two-temperature effects on these amplitude ratios with angle of incidence are depicted graphically. Some special and particular cases are also deduced.

Propagation of plane waves of magneto-thermoelastic medium with voids influenced by the gravity and laser pulse under G-N theory

2016 ◽  
Vol 12 (2) ◽  
pp. 326-344 ◽  
Author(s):  
Mohamed Ibrahim A Othman ◽  
Mohamed I. M. Hilal
Keyword(s):  
Magnetic Fields ◽  
Laser Pulse ◽  
Pulse Heating ◽  
Volume Fraction ◽  
Plane Waves ◽  
Mode Analysis ◽  
Thermoelastic Medium ◽  
Content Type ◽  
Thermoelastic Material ◽  
Laser Pulse Heating

Purpose – The purpose of this paper is to investigate the influence of the gravity and the magnetic fields on the plane waves in a homogenous, linear and isotropic thermoelastic medium subjected to the laser pulse heating. Design/methodology/approach – The problem has been solved analytically and numerically by using the normal mode analysis. Findings – Numerical results for the temperature, the displacement components, the stress components and the volume fraction were presented graphically and analyzed the results. The graphical results indicate that the effect of gravity and magnetic fields are observable physical effects on the porous thermoelastic material heated by a laser pulse. Comparisons are made with the results in the absence and presence of the gravity and the magnetic fields, also at various times. Originality/value – In the present work, the authors shall formulate a 2-D problem for the propagation of plane waves on the porous thermoelastic material influenced by the gravity and the magnetic fields subjected to a laser pulse heating act as a thermal shock. A comparison is also made between the two types II and III of Green-Naghdi theory in the absence and the presence of the gravity and the magnetic fields. Such problems are very important in many dynamical systems.

scholarly journals Reflection of Plane Waves from Surface of a Generalized Thermo-Viscoelastic Porous Solid Half-Space with Impedance Boundary Conditions

2020 ◽  
Vol 22 (4) ◽  
pp. 1483-1496
Author(s):  
Baljeet Singh
Keyword(s):  
Boundary Conditions ◽  
Half Space ◽  
Plane Waves ◽  
Angle Of Incidence ◽  
Amplitude Ratios ◽  
Impedance Boundary ◽  
Reflected Waves ◽  
Material Parameters ◽  
Impedance Boundary Conditions ◽  
Impedance Parameter

AbstractA phenomenon of reflection of plane waves from a thermally insulated surface of a solid half-space is studied in context of Lord-Shulman theory of generalized thermo-viscoelasticity with voids. The governing equations of generalized thermo-viscoelastic medium with voids are specialized in x–z plane. The plane wave solution of these equations shows the existence of three coupled longitudinal waves and a shear vertical wave in a generalized thermo-viscoelastic medium with voids. For incident plane wave (longitudinal or shear), three coupled longitudinal waves and a shear vertical wave reflect back in the medium. The mechanical boundary conditions at free surface of solid half-space are considered as impedance boundary conditions, in which the shear force tractions are assumed to vary linearly with the tangential displacement components multiplied by the frequency. The impedance corresponds to the constant of proportionality. The appropriate potentials of incident and reflected waves in the half-space will satisfy the required impedance boundary conditions. A non-homogeneous system of four equations in the amplitude ratios of reflected waves is obtained. These amplitude ratios are functions of material parameters, impedance parameter, angle of incidence, thermal relaxation and speeds of plane waves. Using relevant material parameters for medium, the amplitude ratios are computed numerically and plotted against certain ranges of impedance parameter and the angle of incidence.

scholarly journals Wave propagation in a microstretch thermoelastic diffusion solid

2015 ◽  
Vol 23 (1) ◽  
pp. 127-170 ◽  
Author(s):  
Rajneesh Kumar
Keyword(s):  
Half Space ◽  
Plane Waves ◽  
Inviscid Fluid ◽  
Angle Of Incidence ◽  
Amplitude Ratios ◽  
Transverse Waves ◽  
Thermoelastic Diffusion ◽  
Transmitted Waves ◽  
Energy Ratios ◽  
The Media

Abstract The present article deals with the two parts: (i) The propagation of plane waves in a microstretch thermoelastic diffusion solid of infinite extent. (ii) The reflection and transmission of plane waves at a plane interface between inviscid fluid half-space and micropolar thermoelastic diffusion solid half-space. It is found that for two-dimensional model, there exist four coupled longitudinal waves, that is, longitudinal displacement wave (LD), thermal wave (T), mass diffusion wave (MD) and longitudinal microstretch wave (LM) and two coupled transverse waves namely (CD-I and CD-II waves). The phase velocity, attenuation coefficient, specific loss and penetration depth are computed numerically and depicted graphically. In the second part, it is noticed that the amplitude ratios of various reflected and transmitted waves are functions of angle of incidence, frequency of incident wave and are influenced by the microstretch thermoelastic diffusion properties of the media. The expressions of amplitude ratios and energy ratios are obtained in closed form. The energy ratios have been computed numerically for a particular model. The variations of energy ratios with angle of incidence for thermoelastic diffusion media in the context of Lord-Shulman (L-S) [1] and Green-Lindsay (G-L) [2] theories are depicted graphically. Some particular cases are also deduced from the present investigation.

A novel model of plane waves of two-temperature fiber-reinforced thermoelastic medium under the effect of gravity with three-phase-lag model

2019 ◽  
Vol 29 (12) ◽  
pp. 4788-4806 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
Samia Said ◽  
Marin Marin
Keyword(s):  
Energy Dissipation ◽  
Plane Waves ◽  
Mode Analysis ◽  
Phase Lag ◽  
Fiber Reinforced ◽  
Thermoelastic Medium ◽  
Content Type ◽  
Three Phase ◽  
Novel Model ◽  
Two Temperature

Purpose In the present paper, the three-phase-lag (3PHL) model, Green-Naghdi theory without energy dissipation (G-N II) and Green-Naghdi theory with energy dissipation (G-N III) are used to study the influence of the gravity field on a two-temperature fiber-reinforced thermoelastic medium. Design/methodology/approach The analytical expressions for the displacement components, the force stresses, the thermodynamic temperature and the conductive temperature are obtained in the physical domain by using normal mode analysis. Findings The variations of the considered variables with the horizontal distance are illustrated graphically. Some comparisons of the thermo-physical quantities are shown in the figures to study the effect of the gravity, the two-temperature parameter and the reinforcement. Also, the effect of time on the physical fields is observed. Originality/value To the best of the author’s knowledge, this model is a novel model of plane waves of two-temperature fiber-reinforced thermoelastic medium, and gravity plays an important role in the wave propagation of the field quantities. It explains that there are significant differences in the field quantities under the G-N II theory, the G-N III theory and the 3PHL model because of the phase-lag of temperature gradient and the phase-lag of heat flux.

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