scholarly journals The elastic wave motions for a photothermal medium of a dual-phase-lag model with an internal heat source and gravitational field

2016 ◽  
Vol 94 (4) ◽  
pp. 400-409 ◽  
Author(s):  
Kh. Lotfy

In this work, the dual-phase-lag (DPL) heat transfer model is introduced to study the problem of an isotropic generalized thermoelastic medium with an internal heat source that is moving with a constant speed. Thermal loading at the free surface of a semi-infinite semiconconducting medium coupled plasma waves with the effect of mechanical force during a photothermal process to study the effect of a gravity field. Harmonic wave analysis is used to obtain exact expressions for the considered variables, also the carrier density coefficients were obtained analytically. The variations of the considered variables through the horizontal distance are illustrated graphically under the effects of several parameters based on the DPL model. The results are discussed and depicted graphically.

2015 ◽  
Vol 11 (2) ◽  
pp. 297-318 ◽  
Author(s):  
Samia M Said

Purpose – The purpose of this paper is to investigate the effect of rotation and a magnetic field on the wave propagation in a generalized thermoelastic problem for a medium with an internal heat source that is moving with a constant speed. Design/methodology/approach – The formulation is applied to a generalized thermoelastic problem based on the three-phase-lag model and Green-Naghdi theory without energy dissipation. The medium is a homogeneous isotropic thermoelastic in the half-space. Findings – The exact expressions of the displacement components, temperature, and stress components are obtained by using normal mode analysis. Originality/value – Comparisons are made with the results predicted by the two models in the absence and presence of a magnetic field as well as a rotation. A comparison also is made with the results predicted by the two models for two different values of an internal heat source.


2017 ◽  
Vol 13 (1) ◽  
pp. 83-99 ◽  
Author(s):  
Samia M. Said

Purpose The purpose of this paper is to investigate the effect of a hydrostatic initial stress and the gravity field on a fiber-reinforced thermoelastic medium with an internal heat source that is moving with a constant speed. Design/methodology/approach A general model of the equations of the formulation in the context of the three-phase-lag model and Green-Naghdi theory without energy dissipation. Findings The exact expressions for the displacement components, force stresses, and the thermal temperature for the thermal shock problem obtained by using normal mode analysis. Originality/value A comparison made between the results of the two models for different values of a hydrostatic initial stress as well as an internal heat source. Comparisons also made with the results of the two models in the absence and presence of the gravity field as well as the reinforcement.


2011 ◽  
Vol 3 (6) ◽  
pp. 745-758
Author(s):  
Ahmed E. Abouelregal

AbstractThe dual-phase-lag heat transfer model is employed to study the reflection phenomena of P and SV waves from a surface of a semi-infinite magneto-thermoelastic solid. The ratios of reflection coefficients to that of incident coefficients are obtained for P- and SV-wave cases. The results for partition of the energy for various values of the angle of incidence are computed numerically under the stress-free and rigidly fixed thermally insulated boundaries. The reflection coefficients are depending on the angle of incidence, magnetic field, phase lags and other material constants. Results show that the sum of energy ratios is unity at the interface. The results are discussed and depicted graphically.


Author(s):  
Amnah M. Alharbi ◽  
Mohamed I. A. Othman ◽  
Elsayed M. Abd-Elaziz

This study considers a thermoelastic micro-elongated solid which is being heated by a laser pulse in order to investigate the corresponding impact of thermal loading and magnetic field. A laser beam that is non-Gaussian in nature is used to heat the surface of the bounded plane with a pulse duration [Formula: see text][Formula: see text]ps. The dual-phase-lag (DPL) model is considered to develop a better understanding of the problem. Also, the problems are solved using normal mode analysis as well as it helps in attaining the appropriate expressions for micro-rotation, components of displacement, the force stress, couple stress, concentration field, the temperature distribution the scalar micro-elongated function, and the micro-stress. The results obtained from the thermal variations are validated by comparing them to Coupled Theory (CT) of thermo-elasticity, Lord and Shulman (L–S) theory, and the DPL model. The graphical illustration of these comparisons has been presented as it helps in exploring the impacts of the laser pulse at two different times and the magnetic field parameter. The investigation also helped deduce some specific cases of interest.


2011 ◽  
Vol 90-93 ◽  
pp. 3001-3004
Author(s):  
Yong An Li ◽  
Ya Nan Gao ◽  
Ming Wang ◽  
Xue Lai Liu

A computational fluid dynamics (CFD) model is proposed to simulate numerically conjugated heat transfer process of fluid washing out solid with evenly internal heat source in the pipe. Temperature field and velocity field inside the pipe and outside solid are gained by calculation. Based on numerical simulation, the varying regularity of Nusselt number between fluid and solid wall surface is obtained and analyzed. The results show that there are two symmetrical vortexes in the back of solid. The Nusselt number and heat exchange rate dramatically decrease with increasing horizontal distance of top and bottom of solid.


2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Tung T. Lam ◽  
Ed Fong

Transient heat conduction in finite thin films subjected to time-varying surface heat flux incidences at both boundaries and internal heat generation is investigated via the dual-phase-lag (DPL) hyperbolic model. Analytical solution of the temperature profiles inside the solid is derived by using the superposition principle and the method of Fourier series expansion in conjunction with the solution structure theorems. For comparison purposes, the classical diffusion, Cattaneo–Vernotte (C–V) model, and simplified thermomass (TM) models are deduced from the generalized DPL model. This is made possible by adjusting the temperature and heat flux relaxation parameters, and offers the opportunity to examine various interconnected non-Fourier conduction heat transfer characteristics including wave and diffusion effects as well as their interrelationship. Details of this process are examined and results are explored in this study.


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