Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 5
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

This 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.

Go to article

Authors and Affiliations

Manindra Mitra
Rabindra Kumar Bhattacharyya
Download PDF Download RIS Download Bibtex

Abstract

This paper presents the analysis of momentum, angular momentum and heat transfer during unsteady natural convection in micropolar nanofluids. Selected nanofluids treated as single phase fluids contain small particles with diameter size 10-38.4 nm. In particular three water-based nanofluids were analyzed. Volume fraction of these solutions was 6%. The first of the analyzed nanofluids contained TiO2nanoparticles, the second one contained Al2O3nanoparticles, and the third one the Cu nanoparticles.
Go to article

Authors and Affiliations

Kazimierz Rup
Konrad Nering
Download PDF Download RIS Download Bibtex

Abstract

The aim of this paper is to study the applicability of the theory of micropolar fluids to modelling and calculating flows in microchannels depending on the geometrical dimension of the flow field. First, it will be shown that if the characteristic linear dimension of the flow becomes appropriately large, the equations describing the micropolar fluid flow can be transformed into Navier-Stokes equations. Next, Poiseuille flows in a microchannel is studied in detail. In particular, the maximal cross-sectional size of the channel for which the micropolar effects of the fluid flow become important will be established. The experimentally determined values of rheological constants of the fluid have been used in calculations.

Go to article

Authors and Affiliations

A. Kucaba-Piętal
Download PDF Download RIS Download Bibtex

Abstract

The problem considered is that of an isotropic, micropolar thermoelastic medium with voids subjected to the Thomson effect. The solution to the problem is presented in the context of the refined multiphase- lags theory of thermoelasticity. The normal mode analysis was used to obtain the analytical expressions of the considered variables. The nondimensional displacement, temperature, microrotation, the change in the volume fraction field and stress of the material are obtained and illustrated graphically. The variations of these quantities have been depicted graphically in the refined-phase-lag theory, Green and Naghdi theory of type II, Lord and Shulman theory and a coupled theory. The effects of the Thomson parameter and phase lag parameters on a homogeneous, isotropic, micropolar thermoelastic material with voids are revealed and discussed. Some particular cases of interest are deduced from the present investigation.
Go to article

Bibliography

[1] Biot M.A.: Thermoelasticity and irreversible thermodynamics. J. Appl. Phys. 7(1956), 3, 240–253.
[2] Lord H.W., Shulman Y.: A generalized dynamical theory of thermoelasticity. J. Mech. Phys. Sol. 15(1967), 5, 299–309.
[3] Green A.E., Lindsay K.A.: Thermoelasticity. J. Elast. 2(1972), 1, 1–7.
[4] Green A.E., Naghdi P.M.: A re-examination of the basic postulates of thermosmechanics. Proc. R. Soc. Lond. A 432(1991), 1885, 171–194.
[5] Green A.E., Naghdi P.M.: On undamped heat wave in elastic solids. J. Therm. Stress. 15(1992), 2, 253–264.
[6] Green A.E., Naghdi P.M.: Thermoelasticity without energy dissipation. J. Elast. 31(1993), 189–209.
[7] Tzou D.Y.: The generalized lagging response in small-scale and high-rate heating. Int. J. Heat Mass Trans. 38(1995), 17, 3231–3240.
[8] Tzou D.Y.: A unified field approach for heat conduction from macro- to microscales. J. Heat Trans. 117(1995), 1, 8–16.
[9] Roy Choudhuri S.K.: On a thermoelastic three-phase-lag model. J. Therm. Stress. 30(2007), 3, 231–238.
[10] Eringen A.C.: Linear theory of micropolar elasticity. ONR Techn. Rep. 29 (School of Aeronautics, Aeronautics and Engineering Science), Purdue Univ., West Lafayett 1965.
[11] Eringen A.C.: A unified theory of thermomechanical materials. Int. J. Eng. Sci. 4(1966), 2, 179–202.
[12] Eringen A.C.: Linear theory of micropolar elasticity. J. Math. Mech. 15(1966), 6, 909–924.
[13] Nowacki W.: Couple stresses in the theory of thermoelasticity III. Bull. Acad. Pol. Sci. Tech. Ser. Sci. Tech. 14(1966), 8, 801–809.
[14] Tauchert T.R., Claus Jr. W.D., Ariman T.: The linear theory of micropolar thermo- elasticity. Int. J. Eng. Sci. 6(1968), 1, 36–47.
[15] Nowacki W., Olszak W. (Eds.): Micropolar Thermoelasticity. CISM Courses and Lectures 151, Springer-Verlag, Vienna 1974.
[16] Dhaliwal R.S., Singh A.: Micropolar thermoelasticity. In: Thermal Stresses II (R.B. Hetnarski, Ed.), Elsevier, Amsterdam 1987.
[17] Marin M., Nicaise S.: Existence and stability results for thermoelastic dipolar bodies with double porosity. Continuum Mech. Thermodyn. 28(2016), 6, 1645–1657.
[18] Marin M., Ellahi R., Chirila A.: On solutions of Saint–Venant’S problem for elastic dipolar bodies with voids. Carpathian J. Math. 33(2017), 2, 219–232.
[19] Othman M.I.A., Hasona W.M., Abed-Elaziz E.M.: Effect of rotation on micropolar generalized thermoelasticity with two temperatures using a dual-phase lag model. Can. J. Phys. 92(2014), 2, 148–159.
[20] Othman M.I.A., Hasona W.M., Abed-Elaziz E.M.: The influence of thermal loading due to laser pulse on generalized micropolar thermoelastic solid with comparison of different theories. Multi. Model. Mater. Struct. 10(2014), 3, 328–345.
[21] Chandrasekharaiah D.S.: Heat flux dependent micropolar thermoelasticity. Int. J. Eng. Sci. 24(1986), 8, 1389–1395.
[22] Othman M.I.A., Hasona W.M., Abed-Elaziz E.M.: Effect of rotation and initial stresses on generalized micropolar thermoelastic medium with three-phase-lag. J. Comput. Theor. Nanosci. 12(2015), 9, 2030–2040.
[23] Othman M.I.A., Abed-Elaziz E.M.: Effect of rotation and gravitational on a micropolar magneto-thermoelastic medium with dual-phase-lag model. Microsyst. Tech. 23(2017), 10, 4979–4987.
[24] Othman M.I.A., Abd-alla A.N., Abed-Elaziz E.M.: Effect of heat laser pulse on wave propagation of generalized thermoelastic micropolar medium with energy dissipation. Ind. J. Phys. 94(2020), 3, 309–317.
[25] Cowin S.C., Nunziato J.W.: Linear elastic materials with voids. J. Elast. 13(1983), 2, 125–147.
[26] Othman M.I.A., Abed–Elaziz E.M.: The effect of thermal loading due to laser pulse in generalized thermoelastic medium with voids in dual-phase-lag model. J. Therm. Stress. 38(2015), 9, 1068–1082.
[27] Abd-Elaziz E.M., Othman M.I.A.: Effect of Thomson and thermal loading due to laser pulse in a magneto-thermoelastic porous medium with energy dissipation. ZAMM-Z. Angew. Math. Me. 99(2019), 8, 201900079.
[28] Abd-Elaziz E.M., Marin M., Othman M.I.A.: On the effect of Thomson and initial stress in a thermos-porous elastic solid under G-N electromagnetic theory. Symmetry. 11(2019), 3, 413–430.
[29] Othman M.I.A., Marin M.: Effect of thermal loading due to laser pulse on thermoelastic porous media under G-N theory. Results Phys. 7(2017), 3863–3872.
[30] Othman M.I.A, Abd-Elaziz E.M.: Plane waves in a magneto-thermoelastic solids with voids and microtemperatures due to hall current and rotation. Results Phys. 7(2017), 4253–4263.
[31] Othman M.I.A., Tantawi R.S., Eraki E.E.M.: Effect of rotation on a semi conducting medium with two-temperature under L–S theory. Arch. Thermodyn. 38(2017), 2, 101–122.
[32] Chirita S., Ciarletta M., Tibullo V.: On the thermomechanical consistency of the time differential dual-phase-lag models of heat conduction. Int. J. Heat Mass Tran. 114(2017), 277–285.
[33] https://matlab.mathworks.com/ (accessed 17 Feb. 2021)
Go to article

Authors and Affiliations

Amnah M. Alharbi
1
Elsayed M. Abd-Elaziz
2
Mohamed I.A. Othman
3

  1. Taif University, Department of Mathematics, College of Science, P.O. Box 11099, Taif, 21944, Saudi Arabia
  2. Ministry of Higher Education, Zagazig Higher Institute of Engineering & Technology, Zagazig, Egypt
  3. Zagazig University, Department of Mathematics, Faculty of Science, P.O. Box 44519, Zagazig, Egypt
Download PDF Download RIS Download Bibtex

Abstract

In this paper, we investigate a problem on reflection and transmission of plane-waves at an interface between two dissimilar half-spaces of a transversely isotropic micropolar piezoelectric material. The entire model is assumed to rotate with a uniform angular velocity. The governing equations of rotating and transversely isotropic micropolar piezoelectric medium are specialized in a plane. Plane-wave solutions of two-dimensional coupled governing equations show the possible propagation of three coupled plane-waves. For an incident plane-wave at an interface between two dissimilar half-spaces, three reflected and three transmitted waves propagate with distinct speeds. The connections between the amplitude ratios of reflected and transmitted waves are obtained. The expressions for the energy ratios of reflected and transmitted waves are also obtained. A numerical example of the present model is considered to illustrate the effects of rotation on the speeds and energy ratios graphically.
Go to article

Authors and Affiliations

Baljeet Singh
1
Asha Sangwan
2
Jagdish Singh
3

  1. Department of Mathematics, Post Graduate Government College, Sector 11, Chandigarh, 160011, India
  2. Department of Mathematics, Government College, Sampla, Rohtak, 124001, Haryana, India
  3. Department of Mathematics, Maharshi Dayanand University, Rohtak, 124001, Haryana, India

This page uses 'cookies'. Learn more