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

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.

Author(s):  
Nor Athirah Mohd Zin ◽  
Ahmad Qushairi Mohamad ◽  
Ilyas Khan ◽  
Sharidan Shafie

The unsteady magnetohydrodynamic (MHD) free convection flow of Jeffrey fluid embedded in porous medium past an oscillating vertical plate generated by thermal radiation with ramped wall temperature is investigated. The incompressible fluid is taken electrically conducting under the action of transverse magnetic field towards the flow. Constitutive relation of Jeffrey fluid is employed to model the governing equations in terms of partial differential equations with some physical conditions. The transformed dimensionless governing equations are solved analytically using Laplace transform technique. The impact of various pertinent parameters namely material parameter of Jeffrey fluid , dimensionless parameter of Jeffrey fluid , phase angle , Hartmann number , permeability parameter , Grashof number , Prandtl number , radiation parameter  and dimensionless time  on velocity and temperature distributions are presented graphically and discussed in details. It is observed that, the permeability parameter tend to retard the fluid velocity for ramped wall temperature but enhance the velocity for an isothermal plate. Besides that, this study shows, the amplitude of velocity and temperature fields for ramped wall temperature are always lower than isothermal plate. A comparison with the existing published work is also provided to confirm the validity of the present results and an excellent agreement are found. 


2015 ◽  
Vol 70 (6) ◽  
pp. 397-401 ◽  
Author(s):  
Ilyas Khan

AbstractIn this note, we investigate the unsteady free convection flow of a Jeffrey fluid past an infinite isothermal vertical plate. Exact solutions are obtained using the Laplace transform technique. These solutions are expressed in terms of exponential and complementary error functions, and satisfy all imposed initial and boundary conditions as well as the governing equations. The expression for the shear stress is also evaluated. The corresponding solutions for a Newtonian fluid can be easily obtained as a special case. It is found from the velocity and shear stress solutions that they strongly depend on the material parameters of a Jeffrey fluid. The exact solutions obtained here can be used as a benchmark for checking the correctness of other approximate or numerical solutions. In addition, this note will help in understanding the characteristics of non-Newtonian fluid flows that are subject to free convection due to buoyancy force.


2016 ◽  
Vol 13 (10) ◽  
pp. 6482-6487
Author(s):  
Ilyas Khan ◽  
Tarek Nabil Ahmed Abdelhameed ◽  
L. C. C Dennis

Heat transfer due to free convection flow in eccentric-concentric rotation of a disk and fluid at infinity is studied in this work Exact solutions for velocity and temperature are obtained by using the Laplace transform technique. The performed calculations disclose that the free convection parameter, Prandtl number, radiation parameter, and dimensionless time have strong influence on fluid velocity and temperature. The graphs are presented for such influence and examined carefully.


2017 ◽  
Vol 13 (4) ◽  
pp. 654-658 ◽  
Author(s):  
Asma Khalid ◽  
Ilyas Khan ◽  
Sharidan Shafie

An analytical investigation is carried out to study the unsteady free convection flow of micropolar fluids over an oscillating vertical plate. Wall couple stress is engaged at the bounding plate with isothermal temperature. Problem is modelled in terms of coupled partial differential equations together with some physical conditions and then written in non-dimensional form. Exact solutions are obtained using the Laplace transform technique. Analytical results of velocity, microrotation and temperature are plotted in graphs and discussed for various embedded parameters. Excellent validation of present results is achieved with existing results in literature. It is observed that, the velocity is smaller for micropolar fluids than for Newtonian fluids.


1970 ◽  
Vol 67 (3) ◽  
pp. 677-688
Author(s):  
P. C. Sinha ◽  
Punyatma Singh

The paper deals with the free convection flow along a vertical plate moving arbitrarily in its own plane. The basic equations of the boundary-layer flow and heat transfer are linearized and the first two approximations are considered. The first approximation is the case of steady-state free convection flow while the second approximation is the response of the fluid velocity and temperature fields to the motion of the plate for which limiting solutions are obtained by the Laplace transform technique in two regions; namely, for large times and for small times. The particular case when the plate is given an impulsive start at t = 0 is investigated in detail. It is shown how the skin friction and the rate of heat transfer at the plate respond to the motion of the plate.


2016 ◽  
Vol 78 (3-2) ◽  
Author(s):  
Arshad Khan ◽  
Ilyas Khan ◽  
Sharidan Shafie

Effects of Newtonian heating and mass diffusion on magnetohydrodynamic free convection flow over a vertical plate that applies arbitrary shear stress to the fluid is studied. The fluid is considered electrically conducting and passing through a porous medium. The influence of thermal radiation in the energy equations is also considered. General solutions of the problem are obtained in closed form using the Laplace transform technique. They satisfy the governing equations, initial and boundary conditions and can set up a huge number of exact solutions correlatives to various fluid motions. The effects of various parameters on velocity profiles are shown graphically and discussed in details


2013 ◽  
Vol 62 (3) ◽  
Author(s):  
Muhamad Najib Zakaria ◽  
Abid Hussanan ◽  
Ilyas Khan ◽  
Sharidan Shafie

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.


Author(s):  
Muhammad Saqib ◽  
Ilyas Khan ◽  
Sharidan Shafie

This article presents the generalization of the unsteady MHD free convection flow of non-Newtonian sodium alginate-ferrimagnetic nanofluid in two infinite vertical parallel plates. The different shape (blade, brick, cylinder, and platelet) ferrimagnetic nanoparticles are dissolved in the non-Newtonian sodium alginate (SA) as base fluid to form non-Newtonian nanofluids. The Jeffrey fluid model together with energy equation is considered to demonstrate the flow. The Atangana–Baleanu fractional operator is utilized for the generalization of mathematical model. The Laplace transform technique and Zakian's numerical algorithm are used to developed general solutions with a fractional order for the proposed model. The obtained results are computed numerically and presented graphically to understand the physics of pertinent flow parameters. It is noticed that the velocity and temperature profiles are significantly increased with the increasing values of the fractional parameter due to the variation in thermal and momentum boundary layers. In the case of the effect of different shapes of nanoparticles, density is a dominant factor as compared to thermal conductivity, which significantly affects the flow of non-Newtonian nanofluid.


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