Hydromagnetic three-dimensional free convective heat transfer overa stretching surface embedded in a non-Darcian porous medium inthe presence of heat generation or absorption

2005 ◽  
Vol 83 (7) ◽  
pp. 739-751 ◽  
Author(s):  
Emad M Abo-Eldahab ◽  
Mohamed A El Aziz
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Porous Medium ◽  
Differential Equations ◽  
Heat Generation ◽  
Three Dimensional ◽  
Inertial Force ◽  
Shear Stresses ◽  
Viscous Term ◽  
Heat Generation Or Absorption

A general analysis is developed to study fluid-flow and heat-transfer characteristics for steady, three-dimensional flow over a linearly stretching porous vertical surface embedded in a non-Darcian medium. A generalized flow model is used in the present study to include the effects of the macroscopic viscous term and the microscopic inertial force. The flow is subjected to a uniform transverse magnetic field normal to the plate. The effect of internal heat generation or absorption is also considered. The governing three-dimensional partial-differential equations for the present case are transformed into ordinary-differential equations using three-dimensional similarity variables. The resulting equations are solved numerically. Velocity distribution, temperature distribution, surface shear stresses, and wall-heat transfer rate are computed for various values of the Prandtl number, magnetic field parameter, inverse Darcy number, porous-medium inertia coefficient, heat generation/absorption coefficient, and mass-transfer coefficient.PACS No.: 44.30.+v

MHD mixed convection stagnation-point flow of a viscoelastic fluid towards a stretching sheet in a porous medium with heat generation and radiation

2015 ◽  
Vol 93 (5) ◽  
pp. 532-541 ◽  
Author(s):  
M. Modather M. Abdou ◽  
E. Roshdy EL-Zahar ◽  
Ali J. Chamkha
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Porous Medium ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Stagnation Point ◽  
Viscoelastic Fluid ◽  
Heat Generation ◽  
Stretching Sheet ◽  
Heat Transfer Characteristics

An analysis was carried out to study the effect of thermal radiation on magnetohydrodynamic boundary layer flow and heat transfer characteristics of a non-Newtonian viscoelastic fluid near the stagnation point of a vertical stretching sheet in a porous medium with internal heat generation–absorption. The flow is generated because of linear stretching of the sheet and influenced by the uniform magnetic field that is applied horizontally in the flow region. Using a similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically using an accurate implicit finite difference scheme. A comparison of the obtained results with previously published numerical results is done and the results are found to be in good agreement. The effects of the viscoelastic fluid parameter, magnetic field parameter, nonuniform heat source–sink, and the thermal radiation parameter on the heat transfer characteristics are presented graphically and discussed. The values of the skin friction coefficient and the local Nusselt number are tabulated for both cases of assisting and opposing flows.

Stagnation Point Flow through a Porous Medium towards a Radially Stretching Sheet in the Presence of Uniform Suction or Injection and Heat Generation

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Hazem Ali Attia ◽  
Karem Mahmoud Ewis ◽  
Mostafa A. M. Abdeen
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Differential Equations ◽  
Stagnation Point ◽  
Heat Generation ◽  
Stretching Sheet ◽  
Stagnation Point Flow ◽  
Uniform Suction ◽  
Flow Through ◽  
Energy Equations

An analysis is made of the steady laminar axisymmetric stagnation point flow of an incompressible viscous fluid in a porous medium impinging on a permeable radially stretching sheet with heat generation or absorption. A uniform suction or blowing is applied normal to the plate which is maintained at a constant temperature. Similarity transformation is used to transform the governing partial differential equations to ordinary differential equations. The finite difference method and generalized Thomas algorithm are used to solve the governing nonlinear momentum and energy equations. The effects of the uniform suction/blowing velocity, the stretching parameter and the heat generation/absorption coefficient on both the flow field and heat transfer are presented and discussed. The results indicate that increasing the stretching parameter or the suction/blowing velocity decreases both the velocity and thermal boundary layer thicknesses. The effect of the stretching parameter on the velocity components is more apparent for suction than blowing while its effect on the temperature and rate of heat transfer at the wall is clearer in the case of blowing than suction.

Thermal Transport in Laminar Convective Flow of Ferrofluids in the Presence of External Magnetic Field

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Ram Krishna Shah ◽  
Jai Kumar Drave ◽  
Sameer Khandekar
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Reynolds Number ◽  
Magnetic Force ◽  
Three Dimensional ◽  
Inertial Force ◽  
Flow Reynolds Number ◽  
Downstream Flow ◽  
Laminar Forced Convection ◽  
Upstream Flow

Abstract A three-dimensional (3D) numerical investigation is carried out to examine the effect of magnetic field (MF) on laminar forced convection of ferrofluids. Laminar flow (Reynolds number (Re) ≤ 100) of ferrofluid is modeled in a square mini-channel of 2 mm hydraulic diameter in the presence of the MF. A magnetic force is induced in ferrofluids because of the applied MF, which accelerates the upstream flow and decelerates the downstream flow with respect to the magnet's location. The acceleration/deceleration of the flow disrupts the hydrodynamic and thermal boundary layers (BLs), positively affecting the heat transfer. The extent of magnetic influence primarily depends on the Reynolds number and induced magnetic force. At low Re (= 25), where magnetic force dominates over inertial force, the flow of ferrofluid is strongly affected by the MF. This results in a higher augmentation in convective heat transfer. As the Re of the flow is increased to Re = 75, the inertial forces partially overcome the effect of the magnetic force, resulting in a smaller augmentation. The interaction of magnetic and inertia forces is expressed through a dimensionless magnetic Froude number (Frm). The effect of volumetric concentration of nanoparticles, Reynolds number, and the presence of multiple magnets placed along the flow channel on heat transfer is investigated through a parametric study. A correlation has also been proposed to predict the net enhancement in the Nusselt number due to the application of the MF based on the results of the present study.

scholarly journals Unsteady MHD Flow of Cassonnano Fluid with Chemical Reaction, Thermal Radiation and Heat Generation/Absorption

MATEMATIKA ◽  
2019 ◽  
Vol 35 (4) ◽  
pp. 33-52 ◽  
Author(s):  
Nur Azlina Mat Noor ◽  
Sharidan Shafie ◽  
Mohd Ariff Admon
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Chemical Reaction ◽  
Heat Generation ◽  
Transfer Rate ◽  
Nanoparticles Concentration

The hydromagnetic mixed convection flow of Cassonnano fluid under the influence of chemical reaction,thermal radiation and heat generation or absorption is investigated. The flow is induced due to unsteady nonlinearly stretching sheet saturated in a porous medium. The governing nonlinear coupled partial differential equations are converted into the system of coupled ordinary differential equations using similarity transformations and then solved numerically via Keller box method. The effects of pertinent parameters on velocity, temperature and nanoparticles concentration as well as wall shear stress, heat and mass transfer rate are analyzed and displayed graphically. The results for skin friction coefficient and local Nusselt number are compared with previously published work and found to be in good agreement. Findings demonstrate that increase in Casson parameter enhanced the friction factor and heat transfer rate. It is noticed that the heat transfer rate is declined with increment in Brownian motion and thermophoresis parameters. The nanoparticles concentration is seen to be higherin generative chemical reaction and opposite effect is observed in destructive chemical reaction. Increase in unsteadiness parameter decreased the fluid velocity, temperature and nanoparticles concentration. The magnitude of wall shear stress is also reduced with increase in unsteadiness and porous medium parameters.

scholarly journals Effects of variable viscosity and thermal conductivity on unsteady MHD flow of non-Newtonian fluid over a stretching porous sheet

2013 ◽  
Vol 17 (4) ◽  
pp. 1035-1047 ◽  
Author(s):  
Abdel-Gamal Rahman
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Thermal Conductivity ◽  
Porous Medium ◽  
Differential Equations ◽  
Newtonian Fluid ◽  
Variable Viscosity ◽  
Mhd Flow ◽  
Transverse Magnetic ◽  
Electrically Conducting

The unsteady flow and heat transfer in an incompressible laminar, electrically conducting and non-Newtonian fluid over a non-isothermal stretching sheet with the variation in the viscosity and thermal conductivity in a porous medium by the influence of an external transverse magnetic field have been obtained and studied numerically. By using similarity analysis the governing differential equations are transformed into a set of non-linear coupled ordinary differential equations which are solved numerically. Numerical results were presented for velocity and temperature profiles for different parameters of the problem as power law parameter, unsteadiness parameter, radiation parameter, magnetic field parameter, porous medium parameter, temperature buoyancy parameter, Prandtl parameter, modified Eckert parameter, Joule heating parameter , heat source/sink parameter and others. A comparison with previously published work has been carried out and the results are found to be in good agreement. Also the effects of the pertinent parameters on the skin friction and the rate of heat transfer are obtained and discussed numerically and illustrated graphically.

Influence of rotating magnetic field on Maxwell saturated ferrofluid flow over a heated stretching sheet with heat generation/absorption

2019 ◽  
Vol 20 (5) ◽  
pp. 502 ◽  
Author(s):  
Aaqib Majeed ◽  
Ahmed Zeeshan ◽  
Farzan Majeed Noori ◽  
Usman Masud
Keyword(s):  
Magnetic Field ◽  
Temperature Field ◽  
Velocity Field ◽  
Differential Equations ◽  
Heat Transport ◽  
Viscous Dissipation ◽  
Heat Generation ◽  
Fluid Motion ◽  
Numerical Procedure ◽  
The Impact

This article is focused on Maxwell ferromagnetic fluid and heat transport characteristics under the impact of magnetic field generated due to dipole field. The viscous dissipation and heat generation/absorption are also taken into account. Flow here is instigated by linearly stretchable surface, which is assumed to be permeable. Also description of magneto-thermo-mechanical (ferrohydrodynamic) interaction elaborates the fluid motion as compared to hydrodynamic case. Problem is modeled using continuity, momentum and heat transport equation. To implement the numerical procedure, firstly we transform the partial differential equations (PDEs) into ordinary differential equations (ODEs) by applying similarity approach, secondly resulting boundary value problem (BVP) is transformed into an initial value problem (IVP). Then resulting set of non-linear differentials equations is solved computationally with the aid of Runge–Kutta scheme with shooting algorithm using MATLAB. The flow situation is carried out by considering the influence of pertinent parameters namely ferro-hydrodynamic interaction parameter, Maxwell parameter, suction/injection and viscous dissipation on flow velocity field, temperature field, friction factor and heat transfer rate are deliberated via graphs. The present numerical values are associated with those available previously in the open literature for Newtonian fluid case (γ 1 = 0) to check the validity of the solution. It is inferred that interaction of magneto-thermo-mechanical is to slow down the fluid motion. We also witnessed that by considering the Maxwell and ferrohydrodynamic parameter there is decrement in velocity field whereas opposite behavior is noted for temperature field.

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