scholarly journals Heat and Mass Transfer of Unsteady Hydromagnetic Free Convection Flow Through Porous Medium Past a Vertical Plate with Uniform Surface Heat Flux

2017 ◽  
Vol 47 (3) ◽  
pp. 25-58 ◽  
Author(s):  
Mohamed Abd El-Aziz ◽  
Aishah S. Yahya
Keyword(s):  
Mass Transfer ◽  
Heat Flux ◽  
Porous Medium ◽  
Free Convection ◽  
Heat And Mass Transfer ◽  
Transport Model ◽  
Convection Flow ◽  
Physical Parameters ◽  
Free Convection Flow ◽  
Laplace Transform Technique

AbstractSimultaneous effects of thermal and concentration diffusions in unsteady magnetohydrodynamic free convection flow past a moving plate maintained at constant heat flux and embedded in a viscous fluid saturated porous medium is presented. The transport model employed includes the effects of thermal radiation, heat sink, Soret and chemical reaction. The fluid is considered as a gray absorbing-emitting but non-scattering medium and the Rosseland approximation in the energy equations is used to describe the radiative heat flux for optically thick fluid. The dimensionless coupled linear partial differential equations are solved by using Laplace transform technique. Numerical results for the velocity, temperature, concentration as well as the skin friction coefficient and the rates of heat and mass transfer are shown graphically for different values of physical parameters involved.

Unsteady free convection flow past a periodically accelerated vertical plate with Newtonian heating

2016 ◽  
Vol 26 (7) ◽  
pp. 2119-2138 ◽  
Author(s):  
M.C. Raju ◽  
S.V.K. Varma ◽  
A.J. Chamkha
Keyword(s):  
Mass Transfer ◽  
Free Convection ◽  
Skin Friction ◽  
Heat And Mass Transfer ◽  
Convection Flow ◽  
Convection Boundary Layer ◽  
Physical Parameters ◽  
Content Type ◽  
Flow Past ◽  
Laplace Transform Technique

Purpose The purpose of this paper is to present an analytical study for a problem of unsteady free convection boundary layer flow past a periodically accelerated vertical plate with Newtonian heating (NH). Design/methodology/approach The equations governing the flow are studied in the closed form by using the Laplace transform technique. The effects of various physical parameters are studied through graphs and the expressions for skin friction, Nusselt number and Sherwood number are also derived and discussed numerically. Findings It is observed that velocity, concentration and skin friction decrease with the increasing values of Sc whereas temperature distribution decreases in the increase in Pr in the presence of NH. Research limitations/implications This study is limited to a Newtonian fluid. This can be extended for non-Newtonian fluids. Practical implications Heat and mass transfer frequently occurs in chemically processed industries, distribution of temperature and moisture over agricultural fields, dispersion of fog and environment pollution and polymer production. Social implications Free convection flow of coupled heat and mass transfer occurs due to the temperature and concentration differences in the fluid as a result of driving forces. For example, in atmospheric flows, thermal convection resulting from heating of the earth by sunlight is affected differences in water vapor concentration. Originality/value The authors have studied heat and mass transfer effects on unsteady free convection boundary layer flow past a periodically accelerated vertical surface with NH, where the heat transfer rate from the bounding surface with a finite heat capacity is proportional to the local surface temperature, and which is usually termed as conjugate convective flow. The equations governing the flow are studied in the closed form by using the Laplace transform technique. The effects of various physical parameters are studied through graphs and the expression for skin friction also derived and discussed.

scholarly journals Finite element analysis for unsteady MHD heat and mass transfer free convection flow of polar fluids past a vertical moving porous plate in a porous medium with heat generation and thermal diffusion

2014 ◽  
Vol 11 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Bala Siddulu Malga ◽  
Naikoti Kishan
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Finite Element ◽  
Porous Medium ◽  
Free Convection ◽  
Heat And Mass Transfer ◽  
Heat Generation ◽  
Convection Flow ◽  
Free Convection Flow ◽  
Polar Fluid

The unsteady two-dimensional magnetohydrodynamic heat and mass transfer free convection flow of an incompressible viscous electrically conducting polar fluid through a porous medium past a semi-infinite vertical porous moving plate in the presence of a transverse magnetic field with thermal diffusion and heat generation is considered. The plate moves with a constant velocity in the longitudinal direction and the free stream velocity follows an exponentially increasing or decreasing. A uniform magnetic field acts perpendicularly to the porous surface which absorbs the polar fluid with a suction velocity varying with time. The equations of conservation of mass, momentum, energy and concentration which govern the case study of heat and mass transfer flow have been obtained. The equations have been solved numerically by Galerkin finite element method. The effect of various flow parameters are presented graphically. Representative results for velocity profiles, temperature profiles and concentration profiles are obtained for several values of pertinent parameters which are of physical and engineering interest.DOI: http://dx.doi.org/10.3329/jname.v11i1.12844

The Effects of Radiation on Free Convection Flow with Ramped Wall Temperature in Brinkman Type Fluid

2013 ◽  
Vol 62 (3) ◽  
Author(s):  
Muhamad Najib Zakaria ◽  
Abid Hussanan ◽  
Ilyas Khan ◽  
Sharidan Shafie
Keyword(s):  
Nusselt Number ◽  
Free Convection ◽  
Laplace Transform ◽  
Vertical Plate ◽  
Convection Flow ◽  
Physical Parameters ◽  
Governing Equations ◽  
Free Convection Flow ◽  
Laplace Transform Technique ◽  
Effects Of Radiation

The present paper is on study of the influence of radiation on unsteady free convection flow of Brinkman type fluid near a vertical plate containing a ramped temperature profile. Using the appropriate variables, the basic governing equations are reduced to nondimensional equations valid with the imposed initial and boundary conditions. The exact solutions are obtained by using Laplace transform technique. The influence of radiation near a ramped temperature plate is also compared with the flow near a plate with constant temperature. The numerical computations are carried out for various values of the physical parameters such as velocity, temperature, skin friction and Nusselt number and presented graphically.

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