Magnetic Field Of Uniform Strength Research Articles

Span-Wise Fluctuating MHD Convective Flow of a Viscoelastic Fluid through a Porous Medium in a Hot Vertical Channel with Thermal Radiation

An unsteady mixed convection flow of a visco-elastic, incompressible and electrically conducting fluid in a hot vertical channel is analyzed. The vertical channel is filled with a porous medium. The temperature of one of the channel plates is considered to be fluctuating span-wise cosinusoidally, i.e., T*(y*,z*,t*)=T1+(T2−T1)cos⁡(πz*d−ω*t*)$T^* \left( {y^* ,z^* ,t^* } \right) = T_1 + \left( {T_2} - {T_ 1} \right)\cos \left( {{{\pi z^* } \over d} - \omega ^* t^* } \right)$ . A magnetic field of uniform strength is applied perpendicular to the planes of the plates. The magnetic Reynolds number is assumed very small so that the induced magnetic field is neglected. It is also assumed that the conducting fluid is gray, absorbing/emitting radiation and non-scattering. Governing equations are solved exactly for the velocity and the temperature fields. The effects of various flow parameters on the velocity, temperature and the skin friction and the Nusselt number in terms of their amplitudes and phase angles are discussed with the help of figures.

Oscillatory MHD Mass Transfer Channel Flow in a Rotating System with Hall Current

The effects of heat and mass transfer on the flow of an oscillatory convective MHD channelflow of an electrically conducting viscous incompressible fluid in a slip flow regime in the presence of Hall current and thermal radiation are studied. A magnetic field of uniform strength is applied normal to the plates of channel. The two vertical porous plates of the channel are subjected to a constant injection/suction. The entire system rotates about an axis normal to the plates with a uniform angular velocity . A closed form analytical solutions to the equations governing the fluid motion are obtained for the velocity, temperature and concentration fields. The numerical calculations for the velocity, temperature and concentration fields, and the coefficient of skin friction, rate of heat and mass transfer at the plates are performed. The results are presented graphically for different values of the physical parameters involved. It is seen that primary fluid flow is retarded due to angular velocity of the system.

Injection/suction effect on MHD convective flow through porous medium filled in a vertical porous channel with heat radiation and chemical reaction

The paper attempt to investigate the effect of injection/suction on the flow of electrically conducting fluid through a porous channel filled with porous material. A magnetic field of uniform strength is applied perpendicular to the plane of the porous channel. The effect of heat radiation, heat source and chemical reaction has been taken into consideration. The governing equations are solved analytically by using complex variable notation. The expressions for velocity, temperature, concentration, skin friction coefficient, rate of heat transfer and rate of mass transfer have been obtained. The effect of various parameters entering the governing equation have been evaluated numerically and expressed graphically and in tabular form. A detailed discussion is given in the result and discussion section of the research paper.

Chemical reaction and heat source effects on MHD oscillatory flow in an irregular channel

Abstract This paper investigates the effect of heat and mass transfer on MHD oscillatory flow in an asymmetric wavy channel with chemical reaction and heat source. The unsteadiness in the flow is due to an oscillatory pressure gradient across the ends of the channel. A magnetic field of uniform strength is applied in the direction perpendicular to the channel. However, the induced magnetic field is neglected due to the assumption of small magnetic Reynolds number. The temperature difference of the channel is also assumed high enough to induce heat transfer due to radiation. The governing equations are solved analytically by regular perturbation method. The analytical results are evaluated numerically and then are presented graphically to discuss the effects of different parameters entering into the problem. It is observed that the heat transport of a system is more increased in oscillatory flow than in ordinary conduction.

Unsteady MHD Free Convection Flow of a Kuvshinski Fluid Past a Vertical Porous Plate in the Presence of Chemical Reaction and Heat Source/Sink

Unsteady magneto hydrodynamic (MHD) free convection flow of a viscous, incompressible and electrically conducting, well known non-Newtonian fluid named as Kuvshinski fluid past an infinite vertical porous plate in the presence of homogeneous chemical reaction, radiation absorption and heat source/sink is studied analytically. The plate is assumed to move with a constant velocity in the direction of fluid flow. A magnetic field of uniform strength is applied perpendicular to the plate, which absorbs the fluid with a suction that varies with time. The dimensionless governing equations are solved analytically using two terms harmonic and non-harmonic functions. The expressions for the fields of velocity, temperature and concentration are obtained. With the aid of these the expressions for skin friction, Nusselt number and Sherwood number are derived. The effects of various physical parameters on the flow quantities are studied through graphs and tables. For the validity, we have checked our results with previously published work and found in good agreement. Velocity decreases for an increase in visco elastic parameter α2, heat absorption coefficient φ, the chemical reaction parameter γ , the magnetic field parameter M, the Prandtl number Pr, the Schmidt number Sc, and increases for increase in Grashof number Gm, the radiation absorption parameter Q1

Optimal Design of Magnetohydrodynamic Mixed Convection Flow in a Vertical Channel with Slip Boundary Conditions and Thermal Radiation Effects by Using an Entropy Generation Minimization Method

Investigation of the effect of thermal radiation on a fully developed magnetohydrodynamic (MHD) convective flow of a Newtonian, incompressible and electrically conducting fluid in a vertical microchannel bounded by two infinite vertical parallel plates with constant temperature walls through a lateral magnetic field of uniform strength is presented. The Rosseland model for the conduction radiation heat transfer in an absorbing medium and two plates with slip-flow and no-slip conditions are assumed. In addition, the induced magnetic field is neglected due to the assumption of a small magnetic Reynolds number. The non-dimensional governing equations are solved numerically using Runge–Kutta–Fehlberg method with a shooting technique. The channel is optimized based on the Second Law of Thermodynamics by changing various parameters such as the thermal radiation parameter, the temperature parameter, Hartmann number, Grashof to Reynolds ratio, velocity slip length, and temperature jump.

Oscillatory MHD Convective Flow of Second Order Fluid Through Porous Medium in a Vertical Rotating Channel in Slip-Flow Regime with Heat Radiation

An analysis of an oscillatory magnetohydrodynamic (MHD) convective flow of a second order (viscoelastic), incompressible, and electrically conducting fluid through a porous medium bounded by two infinite vertical parallel porous plates is presented. The two porous plates with slip-flow condition and the no-slip condition are subjected respectively to a constant injection and suction velocity. The pressure gradient in the channel varies periodically with time. A magnetic field of uniform strength is applied in the direction perpendicular to the planes of the plates. The induced magnetic field is neglected due to the assumption of a small magnetic Reynolds number. The temperature of the plate with no-slip condition is non-uniform and oscillates periodically with time and the temperature difference of the two plates is assumed high enough to induce heat radiation. The entire system rotates in unison about the axis perpendicular to the planes of the plates. Adopting complex variable notations, a closed form solution of the problem is obtained. The analytical results are evaluated numerically and then presented graphically to discuss in detail the effects of different parameters of the problem. The velocity, temperature and the skin-friction in terms of its amplitude and phase angle have been shown graphically to observe the effects of the viscoelastic parameter γ, rotation parameter Ω, suction parameter λ , Grashof number Gr, Hartmann number M, the pressure A, Prandtl number Pr, radiation parameter N and the frequency of oscillation ω .

Effects of Variable Viscosity and Thermal Conductivity on Unsteady Free Convective Heat and Mass Transfer MHD Flow of Micropolar Fluid with Constant Heat Flux through a Porous Medium

effects of temperature dependent viscosity and thermal conductivity on magneto-hydrodynamic unsteady free convective heat and mass transfer flow of an incompressible micropolar fluid through a porous medium along an infinite vertical plate is studied. A magnetic field of uniform strength is assumed to be applied which makes an angle α with the plane transverse to the direction of the main flow. A similarity parameter σ has been introduced and the suction velocity is considered to be inversely proportional to this time dependent parameter. The partial differential equations governing the flow, heat and mass transfer of the problem are transformed into dimensionless form of ordinary differential equations by using similarity substitutions. The governing boundary value problems are then solved numerically using Runge-Kutta shooting method. The effects of various parameters, viz. viscosity parameter, thermal conductivity parameter, mass transfer parameter, coupling constant parameter, Grashoff number, Prandtl number, Schmidt number and magnetic parameter on velocity, secondary velocity, micro-rotation, temperature and concentration field are obtained and presented graphically. The Skin-friction, Nusselt number and Sherwood number are also computed and presented in table. Keywordsfluid, variable viscosity, thermal conductivity, heat and mass transfer, MHD Flow, Hall Current

Effect of Radiation on Unsteady MHD Flow of a Chemically Reacting Fluid Past a Hot Vertical Porous Plate: A Finite Difference Approach

The paper deals with the effect of radiation on unsteady free convention flow of a viscous, incompressible, electrically conducting fluid past an infinite hot vertical porous plate embedded in porous medium. A magnetic field of uniform strength is applied normal to the fluid flow. Chemical reaction, viscous dissipation and Heat generation/absorption effects are included. Temperature of the plate is assumed to be span wise cosinusoidally fluctuating with time. In order to establish a mathematical convenience of converging the solution at a finite point ( 1 → η ), the governing equations of the problem are transformed to a new system of co-ordinates and then resulting equations are reduced to coupled non-linear ordinary differential equations of zeroth and first order, using appropriate perturbation technique. These zeroth and first order equations are solved numerically by making use of finite difference method and the simulation is carried out by coding in C-Program. Graphical results for velocity, temperature and concentration fields are presented and Original Research Article

Hall current effect on radiating span-wise fluctuating MHD convective flow through porous medium in a vertical porous channel

An analysis of an unsteady MHD convective flow of an electrically conducting viscous incompressible fluid through porous medium filled in a vertical porous channel is carried out. The two porous plates are subjected to a constant injection and suction velocity as shown in Fig. 1a, b. The temperature of the plate at y*= + 9 2 is assumed to be varying in space and time as T*(y*, z*, t*) = T1 (y*) + (T2 - T1)COS (πz*d -ω*t*). A magnetic field of uniform strength is applied perpendicular to the plates of the channel. The temperature difference between the plates is high enough to induce the heat due to radiation. It is also assumed that the conducting fluid is opticallythin gray gas, absorbing/ emitting radiation and non-scattering. The Hall current effects have also been taken into account. Exact solution of the partial differential equations governing the flow under the prescribed boundary conditions has been obtained for the velocity and the temperature fields. The primary and secondary velocities, temperature and the skin-friction and Nusselt number for the rate of heat transfer in terms of their amplitudes and phase angles have been shown graphically to observe the effects of suction parameter λ, Grashof number Gr, Hartmann number M, Hall parameter H, the permeability of the porous medium K, Prandtl number Pr, radiation parameter N, pressure gradient A and the frequency of oscillation ω. The final results are then discussed in detail in the last section of the paper with the help of figures.

Thermal and Solutal Buoyancy Effect on MHD Boundary Layer Flow of a Visco-Elastic Fluid Past a Porous Plate with Varying Suction and Heat Source in the Presence of Thermal Diffusion

An analytical solution is investigated for a fully developed free convective flow of a visco-elastic incompressible electrically conducting fluid past a vertical porous plate bounded by a porous medium in the presence of thermal diffusion, variable suction and variable permeability. A magnetic field of uniform strength is applied perpendicular to the plate and the presence of heat source is also considered. The novelty of the study is to investigate the effect of thermal diffusion on a visco-elastic fluid in the presence of time dependent variable suction. The importance is due to the applications of this kind of visco-elastic fluids in many industries. The coupled dimensionless nonlinear partial differential equations are transformed into a set of ordinary differential equations by using multiple parameter perturbation on velocity whereas simple perturbation method on temperature and concentration. With corresponds to these, the expressions for skin friction, Nusselt number and Sherwood number are derived. The numerical computations have been studied through figures and tables. The presence of thermal diffusion increases fluid velocity, whereas the influence of the magnetic field reduces it. In the case of heavier species, it is noticed that concentration increases with an increase in Soret number.

Soret effects due to natural convection in a non-Newtonian fluid flow in porous medium with heat and mass transfer

The problem of unsteady MHD free convective, incompressible electrically conducting, non-Newtonian fluid through porous medium bounded by an infinite porous plate in the presence of constant suction has been studied. A magnetic field of uniform strength is assumed to be applied normal to the plate. The equations governing the fluid flow which are highly nonlinear are reduced to linear by using perturbation method and have been solved subject to the relevant boundary conditions. It is noted that the velocity of the fluid is increased as Soret number and suction parameter increase, whereas reverse phenomenon is observed in case of magnetic field strength and sink strength. DOI: http://dx.doi.org/10.3329/jname.v11i2.17563

Heat transfer in MHD oscillatory flow of dusty fluid in a rotating porous vertical channel

An analysis of the unsteady flow of a dusty viscous, incompressible, electrically conducting fluid in a vertical porous channel rotating with constant angular velocity under the influence of periodic pressure gradient is presented. The left porous plate of the channel is subjected to a uniform injection and the right porous plate to same uniform suction respectively. A magnetic field of uniform strength is applied perpendicular to the planes of the plates. The magnetic Reynolds number is assumed to be small enough so that the induced magnetic field is negligible. The whole system rotates in unison about the axis normal to the planes of the plates. Analytical solutions for the velocities and temperatures of the fluid and the dust particles are obtained. The influence of the various parameters appearing in the equations of velocities and temperatures of the fluid and the dust particles have been numerically evaluated and expressed graphically.

Effect of Hall current and rotation on chemically reacting and radiating MHD oscillatory dusty viscoelastic flow through porous vertical channel

The combine effect of the hall current, rotation, radiation and chemical reaction on MHD oscillatory free convective, dusty, viscoelastic, incompressible and electrically conducting fluid in an infinite porous vertical channel has been analysed. A uniform injection/ suction velocity is applied at the plates and uniform magnetic field of uniform strength is applied in the direction normal to the plane of the plates. The entire system rotates about the axis normal to the planes of the plates with uniform angular velocity. The solution of the equations governing the flow are obtained for fluid velocity, dust particle velocity, temperature and concentration profile. The effect of the various parameters entering in the governing equations on flow are evaluated numerically and discussed with the help of graphs and tables.

Soret and Hall Effect on Heat and Mass Transfer in MHD Free Convective Flow Through a Porous Medium in a Vertical Porous Channel

An unsteady free convective flow through porous media of viscous, incompressible, electrically conducting fluid through a vertical porous channel is studied. A magnetic field of uniform strength is applied perpendicular to the vertical channel. The magnetic Reynolds number is assumed very small so that the induced magnetic field is negligible. The injection and suction velocity at both plates are constant. The pressure gradient in the channel varies periodically with time along the axis of the channel. Taking Hall current into account, equations of motion, energy, and concentration are solved. The effects of the various parameters, entering into the problem, on the primary and secondary velocity are shown graphically while the skin friction coefficient, Nusselt number and Sherwood number obtained in terms of amplitude and phase angle are listed in tabular form and discussed.

Effects of Radiation and Soret in the Presence of Heat Source/Sink on Unsteady MHD Flow Past a Semi-infinite vertical plate

The paper deals with the effects of radiation and Soret number variation in the presence of heat source/sink on unsteady laminar boundary layer flow of a chemically reacting fluid along a semi-infinite vertical plate, taking the term Eckert number into account. A magnetic field of uniform strength is applied normal to the flow. The governing boundary layer equations are solved numerically, using Crank-Nicholson method and the simulation is carried out by coding in C-Programme. Graphical results for velocity, temperature and concentration fields and tabular values of Skin-friction, Nusselt and Sherwood numbers are presented and discussed at various parametric conditions. From this study, it is found that the Skin–friction, Nusselt number, temperature and velocity of the fluid increase in the presence heat source and for increasing values Eckert number (Ec).

Hall current effect on viscoelastic (Walter's liquid model-B) MHD oscillatory convective channel flow through a porous medium with heat radiation

An oscillatory MHD convective flow of an incompressible, viscoelastic (Walter's liquid model-B) and electrically conducting fluid through porous medium filled in a vertical porous channel is analyzed. The two porous plates of the channel are subjected to a constant injection and suction velocity as shown in Fig.1. A magnetic field of uniform strength is applied perpendicular to the plates of the channel. The temperature of one of the plates varies periodically and the temperature difference between the two plates is high enough to induce the heat due to radiation. A closed form solution of the purely oscillatory flow is obtained. The velocity, temperature and the skin-friction in terms of its amplitude and phase angle have been shown graphically to observe the effects of viscoelasticity γ, injection/suction parameter λ, Grashof number Gr, Hartmann number M, Hall parameter H, the pressure A, Prandtl number Pr, Radiation parameter N and the frequency of oscillation ω.

Effect of magnetic field on three dimensional fluctuating Couette slip flow past porous plates

An analysis of the three dimensional flow of an viscous incompressible fluid between two horizontal porous flat plates separated by a finite distance in a slip flow regime is carried out under following conditions: the fluid is electrically conducting, the free stream velocity is uniform, the plate is subjected to a sinusoidal transverse suction velocity distribution and a magnetic field of uniform strength is applied in the direction normal to the plate. The influences of the various parameters on the main flow and cross flow velocity and skin friction are discussed with the help of graphs.

Unsteady MHD Free Convective Visco-Elastic Fluid Flow Bounded by an Infinite Inclined Porous Plate in the Presence of Heat Source, Viscous Dissipation and Ohmic Heating

The present study deals with an unsteady magneto hydrodynamic free convective, Viscoelastic, dissipative fluid flow embedded in porous medium bounded by an infinite inclined porous plate in the presence of heat source, and Ohmic heating under the influence of transversely applied magnetic field of uniform strength. The equations governing the fluid flow are solved using a multiple parameter perturbation technique, subject to the relevant boundary conditions. Expressions for velocity and temperature distributions are obtained. Non dimensional skin friction coefficient and the rate of heat transfer in the form of Nusselt number are also derived and illustrated using graphs and tables. The effects of various physical parameters on the above flow quantities are discussed.

Effect of slip condition on viscoelastic mhd oscillatory forced convection flow in a vertical channel with heat radiation

In this paper an oscillatory flow of a viscoelastic, incompressible and electrically conducting fluid through a porous medium bounded by two infinite vertical parallel plates is discussed. One of these plates is subjected to a slip-flow condition and the other to a no-slip condition. The pressure gradient in the channel oscillates with time. A magnetic field of uniform strength is applied in the direction perpendicular to the plates. The induced magnetic field is neglected due to the assumption of a small magnetic Reynolds number. The temperature difference of the two plates is also assumed high enough to induce heat transfer due to radiation. A closed form analytical solution to the problem is obtained. The analytical results are evaluated numerically and then presented graphically to discuss in detail the effects of different parameters entering into the problem. A number of particular cases have been shown by dotted curves in the figures. During the analysis it is found that the physical and the mathematical formulations of the problems by Makinde and Mhone (2005), Mehmood and Ali (2007), Kumar et al. (2010) and Choudhury and Das (2012) are not correct. The correct solutions to all these important oscillatory flow problems are deduced.