Soret and Radiation Effects on Transient MHD Free Convection From an Impulsively Started Infinite Vertical Plate

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
N. Ahmed
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Free Convection ◽  
Thermal Radiation ◽  
Skin Friction ◽  
Vertical Plate ◽  
Soret Effect ◽  
Viscous Drag ◽  
Laplace Transform Technique ◽  
Infinite Vertical Plate

An exact solution to the problem of MHD transient free convection and mass transfer flow of a viscous, incompressible, and electrically conducting fluid past a suddenly started infinite vertical plate taking into account the thermal diffusion as well as the thermal radiation is presented. Assuming the medium to be nonscattered and the fluid to be nongray, emitting–absorbing, and optically thin radiation limit properties, the equations governing the flow and heat and mass transfer are solved by Laplace transform technique. The expressions for the velocity field, the concentration field, the skin friction at the plate in the direction of the flow, and the coefficient of heat transfer and mass transfer from the plate to the fluid have been obtained, and their numerical values for different values of the physical parameters involved in the problem have been demonstrated in graphs and tables, and these are physically interpreted. It is found that the thermal radiation retards the fluid flow whereas the Soret effect accelerates the flow. The viscous drag on the plate is increased under the Soret and magnetic field effects whereas the thermal radiation reduces the skin friction. Further, the rate of heat transfer at the plate increases under thermal radiation effect. Also, in the presence of radiation, the Soret effect results in a steady increase in the mass flux from the fluid to the plate.

RADIATION EFFECTS ON AN UNSTEADY NATURAL CONVECTIVE FLOW OF A NANOFLUID PAST AN INFINITE VERTICAL PLATE

NANO ◽  
2013 ◽  
Vol 08 (01) ◽  
pp. 1350001 ◽  
Author(s):  
P. LOGANATHAN ◽  
P. NIRMAL CHAND ◽  
P. GANESAN
Keyword(s):  
Heat Transfer ◽  
Skin Friction ◽  
Convective Flow ◽  
Radiation Effects ◽  
Vertical Plate ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Skin Friction Coefficient ◽  
Laplace Transform Technique ◽  
Infinite Vertical Plate

An exact analysis is carried out to study the radiation effects on an unsteady natural convective flow of a nanofluid past an impulsively started infinite vertical plate. The nanofluids containing nanoparticles of aluminium oxide, copper, titanium oxide and silver with nanoparticle volume fraction range less than or equal to 0.04 are considered. The partial differential equations governing the flow are solved by Laplace transform technique. The influence of various parameters on velocity and temperature profiles, as well as Nusselt number and skin-friction coefficient, are examined and presented graphically. An increase in radiation parameter and time leads to fall in temperature of the fluid. The presence of nanoparticles and thermal radiation increases the rate of heat transfer and skin friction. The effect of heat transfer is found to be more pronounced in silver water nanofluid than in the other nanofluids. It is observed that the fluid velocity increases with an increase in Grashof number and time. Excellent validation of the present results is achieved with existing results in the literature.

Effects of Mass Transfer and Free-Convection Currents on the Flow Past an Impulsively Started Vertical Plate

1979 ◽  
Vol 46 (4) ◽  
pp. 757-760 ◽  
Author(s):  
V. M. Soundalgekar
Keyword(s):  
Mass Transfer ◽  
Free Convection ◽  
Skin Friction ◽  
Schmidt Number ◽  
Vertical Plate ◽  
Exact Analysis ◽  
Flow Past ◽  
Infinite Vertical Plate

An exact analysis of the effects of mass transfer on the Stokes’ (also Rayleigh’s) problem for an infinite vertical plate has been presented on taking into account the free-convection currents. It has been observed that there is a rise in the velocity due to the presence of a foreign mass. But an increase in Sc (<1), Schmidt number, leads to a fall in the velocity. The skin-friction increases due to the presence of a foreign mass and Sc< 1, but it decreases at Sc = 1.

Effects of Mass Transfer and Free-Convection Currents on the Flow Near a Moving Vertical Plate With Ramped Wall Temperature

2009 ◽  
Author(s):  
M. Narahari ◽  
Binay K. Dutta
Keyword(s):  
Mass Transfer ◽  
Free Convection ◽  
Skin Friction ◽  
Heat And Mass Transfer ◽  
Buoyancy Force ◽  
Vertical Plate ◽  
Flow Temperature ◽  
Thermal Buoyancy ◽  
Laplace Transform Technique ◽  
Thermal Buoyancy Force

A theoretical analysis to the problem of free convection flow induced by an infinite moving vertical plate subject to a ramped surface temperature with simultaneous mass transfer to or from the surface is presented. The plate temperature increases linearly over a specified period of time until it reaches a constant value. Diffusional mass transfer occurs at the surface contributing to the density gradient in the boundary layer. An exact analytical solution to the governing equations for flow, temperature and concentration with coupled boundary conditions in the dimensionless form have been developed using the Laplace transform technique. Heat and mass transfer at the plate are assumed to be purely diffusive in nature. The cases of impulsive start and uniformly accelerating start of the plate are considered and solutions for the flow, temperature and concentration fields are derived. The effects of different system parameters have been studied in terms of relevant dimensionless groups such as Grashof number (Gr), Prandtl number (Pr), Schmidt number (Sc), time (t) and the mass to thermal buoyancy ratio (N). The possible cases of the last parameter, namely N = 0 (the buoyancy force is due to thermal diffusion only), N &gt; 0 (the mass buoyancy force acts in the same direction of thermal buoyancy force) and N &lt; 0 (the mass buoyancy force acts in the opposite direction of thermal buoyancy force) are investigated and their effects on the velocity field and skin-friction are explicitly determined. The ramped temperature boundary condition predictably has an enhancing effect on the skin friction. The mass flux to the plate influences the velocity and hence the skin friction. A critical analysis of the coupled heat and mass transfer phenomena is provided. The free convection near a ramped temperature plate has also been compared with the flow near a plate with constant temperature as a limiting case.

The Effect of Mass Transfer on Free Convection

1960 ◽  
Vol 82 (3) ◽  
pp. 260-263 ◽  
Author(s):  
R. Eichhorn
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Free Convection ◽  
Skin Friction ◽  
Leading Edge ◽  
Temperature Profiles ◽  
Constant Wall Temperature ◽  
Constant Property ◽  
Boundary Layer Equations ◽  
Similar Solutions

Consideration is given to the constant property laminar boundary layer equations with free convection and mass transfer. It is shown that similar solutions are possible for blowing rate distributions varying as the distance from the leading edge raised to the power (n − 1)/4 where n is the exponent in a power law surface temperature distribution. Solutions to the equations in the form of skin friction and heat-transfer parameters, and velocity and temperature profiles are presented for the constant wall temperature case for a fluid with Pr = 0.73. The cases considered range from strong suction to strong blowing. Mass transfer has a pronounced effect on the heat transfer but only a slight effect on the skin friction. In light of the solutions presented, these effects are shown to be physically rational.

scholarly journals Influence of Thermal Radiation on Unsteady MHD Free Convection Flow of Jeffrey Fluid over a Vertical Plate with Ramped Wall Temperature

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Nor Athirah Mohd Zin ◽  
Ilyas Khan ◽  
Sharidan Shafie
Keyword(s):  
Free Convection ◽  
Thermal Radiation ◽  
Wall Temperature ◽  
Vertical Plate ◽  
Convection Flow ◽  
Jeffrey Fluid ◽  
Dimensionless Time ◽  
Free Convection Flow ◽  
Laplace Transform Technique ◽  
The Laplace Transform

Influence of thermal radiation on unsteady magnetohydrodynamic (MHD) free convection flow of Jeffrey fluid over a vertical plate with ramped wall temperature is studied. The Laplace transform technique is used to obtain the analytical solutions. Expressions for skin friction and Nusselt number are also obtained. Results of velocity and temperature distributions are shown graphically for embedded parameters such as Jeffrey fluid parameterλ, Prandtl numberPr, Grashof numberGr, Hartmann numberHa, radiation parameterRd, and dimensionless timeτ. It is observed that the amplitude of velocity and temperature profile for isothermal are always higher than ramped wall temperature.

Analytical Analysis of Magneto-hydrodynamic (MHD) Transient Flow Past a Suddenly Started Infinite Vertical Plate With Thermal Radiation and Ramped Wall Temperature

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
N. Ahmed ◽  
M. Dutta
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Reynolds Number ◽  
Transverse Magnetic Field ◽  
Wall Temperature ◽  
Vertical Plate ◽  
Transverse Magnetic ◽  
Viscous Drag ◽  
Fluid Temperature ◽  
Infinite Vertical Plate

An exact solution to the problem of a magnetohydrodynamic viscous, incompressible free convective flow of an electrically conducting, Newtonian non-Gray fluid past a suddenly started infinite vertical plate with ramped wall temperature in presence of appreciable radiation heat transfer and uniform transverse magnetic field is presented. The fluid is assumed to be optically thin and the magnetic Reynolds number is considered small enough to neglect the induced hydromagnetic effects. The resulting system of the equations governing the flow is solved by adopting Laplace Transform technique in closed form. Detailed computations of the influence of Hartmann number, radiation conduction parameter Q, Reynolds number Re and time t on the variations in the fluid velocity, fluid temperature, and skin friction and Nusselt number at the plate are demonstrated graphically. The results show that the imposition of the transverse magnetic field retards the fluid motion and causes the viscous drag at the plate to fall. The investigation simulates that the fluid temperature drops and the rate of heat transfer from the plate to the fluid gets increased for increasing Reynolds number.

scholarly journals Heat and mass transfer effects on moving vertical plate in the presence of thermal radiation

2004 ◽  
Vol 31 (1) ◽  
pp. 35-46 ◽  
Author(s):  
R. Muthucumaraswamy ◽  
Kumar Senthil
Keyword(s):  
Thermal Radiation ◽  
Radiation Effects ◽  
Vertical Plate ◽  
Variable Temperature ◽  
Radiation Parameter ◽  
Plate Temperature ◽  
Grashof Number ◽  
Laplace Transform Technique ◽  
The Laplace Transform ◽  
Infinite Vertical Plate

Thermal radiation effects on moving infinite vertical plate in the presence variable temperature and mass diffusion is considered. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The plate temperature and the concentration level near the plate are raised linearly with time. The dimensionless governing equations are solved using the Laplace-transform technique. The velocity and skin-friction are studied for different parameters like thermal Grashof number, mass Grashof number, time and radiation parameter. It is observed that the velocity slightly decreases with increasing value of the radiation parameter.

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