Abstract
The effect of boundary conditions on the onset of penetrative electro-thermal-convection (ETC) in a dielectric fluid-saturated porous medium via internal heating is investigated. The lower and upper boundaries are considered to be either rigid or stress-free. The lower boundary is isothermal, while a general Robin-type of thermal boundary condition is invoked at the upper boundary. The eigenvalue problem is formulated and numerical solutions via Galerkin-type of weighted residual technique for (1) lower and upper-rigid (R–R), (2) lower-rigid and upper-free (R–F), (3) lower and upper-free (F–F) boundary combinations. It is found that the values of gravity thermal Rayleigh or electric thermal Rayleigh number influencing the onset of ETC is higher for R–R boundaries and lower for F–F boundaries. As strength of internal heating increases, it is observed that, there is a hasten in the onset of ETC, while an increase in the Biot number, ratio of viscosities and decrease in the Darcy number is to delay the onset of ETC. Several standard results are recovered as special cases from the current study.
Similar content being viewed by others
Abbreviations
- \( a \) :
-
Overall horizontal wave number
- \( Bi \) :
-
Biot number
- d :
-
Thickness of the layer
- \( Da \) :
-
Darcy number
- \( D \) :
-
Differential operator
- \( \vec{E} \) :
-
Electric force field
- \( \vec{g} \) :
-
Acceleration due to gravity
- \( k_{1} \) :
-
Permeability of the porous medium
- \( M \) :
-
Ratio of heat capacities
- \( N_{s} \) :
-
Internal heat source strength
- \( p \) :
-
Pressure
- \( \vec{q} \) :
-
Velocity vector
- \( Q \) :
-
Constant internal heat source strength
- \( R_{e} \) :
-
Electric thermal Rayleigh number
- \( R_{t} \) :
-
Thermal Rayleigh number
- \( t \) :
-
Time
- \( T \) :
-
Temperature
- \( W \) :
-
Amplitude of vertical component of velocity
- \( \alpha \) :
-
Thermal expansion coefficient
- \( \nabla^{2} \) :
-
Laplacian operator
- \( \nabla_{h}^{2} \) :
-
Horizontal Laplacian operator
- \( \varepsilon \) :
-
Dielectric constant
- \( \eta \) :
-
Dielectric constant expansion coefficient
- \( \kappa \) :
-
Thermal diffusivity
- \( \varLambda \) :
-
Ratio of viscosity
- \( \mu \) :
-
Coefficient of dynamic viscosity
- \( \mu \) :
-
Coefficient of effective viscosity
- \( \nu \) :
-
Kinematic viscosity
- \( \phi \) :
-
Electric potential
- \( \varphi_{p} \) :
-
Porosity of the porous medium
- \( \varPhi \) :
-
Amplitude of electric field potential
- \( \rho \) :
-
Density of the fluid
- \( \rho_{e} \) :
-
Free charge
- \( \varTheta \) :
-
Amplitude of temperature field
- \( x,y,z \) :
-
Cartesian co-ordinates
- \( 0 \) :
-
Reference value
- \( f \) :
-
Fluid
- \( b \) :
-
Basic state
References
Chandrasekhar, S.: Hydrodynamic and Hydromagnetic Stability. Oxford University Press, Oxford (1961)
Chang, J.S., Watson, A.: Electromagnetic hydrodynamics. IEEE Trans. Dielectr. Electr. Insul. 1(5), 871–895 (1994)
Char, M.I., Chiang, K.T.: Boundary effects on the Bénard–Marangoni instability under an electric field. Appl. Sci. Res. 52, 331–354 (1994)
Del Rio, J.A., Whitaker, S.: Electrohydrodynamics in porous media. Transp. Porous Media 440, 385–405 (2001)
Landau, L.D., Lifshitz, E.M.: Electrohydrodynamics of Continuous Media. Oxford, New York (1960)
Larsen, J.N.E., Ran, H., Zhang, Y.: Electrodynamic (EHD) cooled laptop. In: 25th Annual IEEE Semiconductor Thermal Measurement and Management Symposium (2009)
Lebon, G., Cloot, A.: Thermodynamical modelling of fluid flows through porous media: application to natural convection. Int. J. Heat Mass Transf. 29(3), 381–390 (1986)
Maekawa, T., Abe, K., Tanasawa, I.: Onset of natural convection under an electric field. Int. J. Heat Mass Transf. 35, 613–621 (1992)
Moreno, R.Z., Bonet, E.J., Trevisan, O.V.: Electric alternating current effects on flow of oil and water in porous media. In: Vafai, K., Shivakumar, P.N. (eds.) Proceedings of the International Conference on Porous Media and Their Applications in Science, pp. 147–172. Engineering and Industry, Hawaiir (1996)
Nield, D.A., Bejan, A.: Convection in Porous Media, Sixteenth edn. Springer, New York (2017)
Roberts, P.H.: Electrohydrodynamic convection. Q. J. Mech. Appl. Math. 22, 211–220 (1969)
Rudraiah, N., Gayathri, M.S.: Effect of thermal modulation on the onset of electrothermoconvection in a dielectric fluid saturated porous medium. ASME J. Heat Transf. 131, 101009–101015 (2009)
Shivakumara, I.S., Nagashree, M.S., Hemalatha, K.: Electrothermoconvective instability in a heat generating dielectric fluid layer. Int. Commun. Heat Mass Transf. 34, 1041–1047 (2007)
Shivakumara, I.S., Ng, C.-O., Nagashree, M.S.: The onset of electrothermoconvection in a rotating Brinkman porous layer. Int. J. Eng. Sci. 9, 946–963 (2011)
Shivakumara, I.S., Lee, J., Vejravelu, K., Akkanagamma, M.: Electrothermal convection in a rotating dielectric fluid layer: effect of velocity and temperature boundary conditions. Int. J. Heat Mass Transf. 55, 2984–2991 (2012)
Shivakumara, I.S., Akkanagamma, M., Ng, C.-O.: Electrothydrodynamic instability of a rotating couple stress dielectric fluid layer. Int. J. Heat Mass Transf. 62, 761–771 (2013)
Shivakumara, I.S., Rudraiah, N., Lee, J., Hemalatha, K.: The onset of Darcy–Brinkman electroconvection in a dielectric fluid saturated porous layer. Trans. Porous Media 90, 509–528 (2011)
Smorodin, B.L., Velard, M.G.: On the parametric excitation of electrothermal instability in a dielectric liquid layer using an alternating electric field. J. Electrost. 50, 205–226 (2001)
Smorodin, B.L.: Stability of plane flow of a liquid dielectric in a transverse alternating electric field. Int. J. Heat Mass Trans. Fluid Dyn. 36, 548–555 (2001)
Sparrow, E.M., Goldstein, R.J., Jonson, V.K.: Thermal instability in a horizontal fluid layer: effect of boundary conditions in a horizontal fluid layer—effect of boundary conditions and non-linear temperature profiles. J. Fluid Mech. 18, 513–528 (1964)
Tassavur, S.: Super Cool ‘EHD Pump’ by NASA Cools Devices in Space, 31st May 2011. http://onlygizmos.com/super-cool-ehd-pump-by-nasa-cools-devices-in-space/2011/05
Taylor, G.I.: Studies in electrohydrodynamics, circulation produced in a drop by an electric field. Proc. R. Soc. Lond. A. 291, 159–166 (1966)
Thoma, A.M., Morari, M.: Control of Fluid Flow. Springer, Berlin (2006)
Turnbull, R.J., Melcher, J.R.: Electrodynamic Rayleigh–Taylor bulk instability. Phys. Fluids 12, 1160–1166 (1969)
Turnbull, R.J.: Effect of dielectrophoretic forces on the Benard instability. Phys. Fluids 12, 1809–1815 (1969)
Acknowledgements
The authors wish to thank the referees for their useful comments. Also, gratefully acknowledge the financial support received in the form of a “Research Fund for Talented Teacher Scheme” from Vision Group of Science & Technology, Government of Karnataka, Bengaluru, India.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Ashwini, R., Nanjundappa, C.E. & Shivakumara, I.S. Penetrative Electro-Thermal-Convection in a Dielectric Fluid-Saturated Porous Layer Via Internal Heating: Effect of Boundary Conditions. Int. J. Appl. Comput. Math 5, 37 (2019). https://doi.org/10.1007/s40819-019-0619-x
Published:
DOI: https://doi.org/10.1007/s40819-019-0619-x