Hall Current Effects Research Articles

Nonlinear radiative heat transfer and Hall effects on a viscous fluid in a semi-porous curved channel

In this paper, effects of Hall currents and nonlinear radiative heat transfer in a viscous fluid passing through a semi-porous curved channel coiled in a circle of radius R are analyzed. A curvilinear coordinate system is used to develop the mathematical model of the considered problem in the form partial differential equations. Similarity solutions of the governing boundary value problems are obtained numerically using shooting method. The results are also validated with the well-known finite difference technique known as the Keller-Box method. The analysis of the involved pertinent parameters on the velocity and temperature distributions is presented through graphs and tables.

Thermo Diffusion and Hall Current Effects on an Unsteady Flow of a Nanofluid under the Influence of Inclined Magnetic Field

In this paper, we investigated the effects of hall current and thermal diffusion on an unsteady flow of a nanofluid in the presence of inclined magnetic field and volume fraction of nanoparticles. We considered copper nanoparticles with base fluid as water and presented dual solutions for water and Cu-water cases. An analytical solution of the problem was performed using perturbation technique. The effects of various non-dimensional governing parameters on velocity, temperature and concentration fields along with the friction factor, local Nusselt and Sherwood numbers are discussed and presented through graphs and tables. To validate the results of the present study we compared the present results with the existed results and found an excellent agreement. Moreover, through this study we observed that an increase in the Hall current parameter increases the velocity profiles and depreciates the friction factor. It is also observed that an increase in Soret number causes to enhance the velocity and concentration boundary layer thicknesses.

The onset of MHD nanofluid convection with Hall current effect

In this paper, the combined effects of Hall current and magnetic field on the onset of convection in an electrically conducting nanofluid layer heated from below is investigated. A physically more realistic boundary condition on the nanoparticle volume fraction is taken i.e. the nanoparticle flux is assumed to be zero rather than prescribing a nanoparticle volume fraction on the rigid impermeable boundaries. The employed model incorporates the effects of Brownian motion and thermophoresis. The resulting eigenvalue problem is solved using the Galerkin method. The results obtained during the analysis are presented graphically for an alumina-water nanofluid. It is observed that the effect of smaller values of the Hall current parameter and the nanoparticle parameters accelerate the onset of convection, while larger values of the Hall current parameter (≥ 15) have no effect on the system stabilities.

Effects of magnetic field and Hall current to the blood velocity and LDL transfer

The magnetic field and Hall current effects have been considered on blood velocity and concentration of low-density lipoprotein (LDL). It is important to observe those effects to the flowing blood in a stenosed artery. The analysis from the obtained results may be useful to some clinical procedures, such as MRI, where the radiologists may have more information in the investigations before cardiac operations could be done. In this study, the uniform magnetic field and Hall current are applied to the Newtonian blood flow through an artery having a cosine-shaped stenosis. The governing equations are coupled with mass transfer and solved employing a finite difference Marker and Cell (MAC) method with an appropriate initial and boundary conditions. The graphical results of velocity profiles and LDL concentration are presented in this paper and the results show that the velocity increases and concentration decreases as Hall parameter increased.

Magnetized laboratory plasma jets: experiment and simulation.

Experiments involving radial foils on a 1MA, 100ns current driver can be used to study the ablation of thin foils and liners, produce extreme conditions relevant to laboratory astrophysics, and aid in computational code validation. This research focuses on the initial ablation phase of a 20μm Al foil (8111 alloy), in a radial configuration, driven by Cornell University's COBRA pulsed power generator. In these experiments ablated surface plasma (ASP) on the top side of the foil and a strongly collimated axial plasma jet are observed developing midway through the current rise. With experimental and computational results this work gives a detailed description of the role of the ASP in the formation of the plasma jet with and without an applied axial magnetic field. This ∼1T field is applied by a Helmholtz-coil pair driven by a slow, 150μs current pulse and penetrates the load hardware before arrival of the COBRA pulse. Several effects of the applied magnetic field are observed: (1) without the field extreme-ultraviolet emission from the ASP shows considerable azimuthal asymmetry while with the field the ASP develops azimuthal motion that reduces this asymmetry, (2) this azimuthal motion slows the development of the jet when the field is applied, and (3) with the magnetic field the jet becomes less collimated and has a density minimum (hollowing) on the axis. PERSEUS, an XMHD code, has qualitatively and quantitatively reproduced all these experimental observations. The differences between this XMHD and an MHD code without a Hall current and inertial effects are discussed. In addition the PERSEUS results describe effects we were not able to resolve experimentally and suggest a line of future experiments with better diagnostics.

Hall Current Effects on Unsteady Mhd Fluid Flow with Radiative Heatflux and Heat Source over a Porous Medium

In this paper the study of unsteady hydromagnectic free flow of viscoelastic fluid (Walter’s B) past an infinite vertical plate through porous medium was conducted. The temperature is assumed to be oscillating with time, also the effects of hall-current is taken in to account. The solution of velocity, temperature and concentration profiles have been obtained. The effects of various parameters on temperature, concentration primary and secondary velocity profiles were presented graphically.

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.

Effects of Hall Currents on the Boundary Layer Flow Induced by an Exponentially Stretching Surface

The objective of the present analysis is to understand the effects of Hall currents and chemical reaction on the unsteady flow of a viscous incompressible fluid past an exponentially stretching sheet in the presence of temperature dependent heat source and thermal radiation with slip effects.

Hall Current Effects on Unsteady MHD Flow in a Rotating Parallel Plate Channel Bound-ed by Porous Bed on the Lower Half—Darcy Lapwood Model

We discussed the unsteady flow of an incompressible viscous fluid in a rotating parallel plate channel bounded on one side by a porous bed under the influence of a uniform transverse magnetic field taking hall current into account. The perturbations are created by a constant pressure gradient along the plates in addition to the non-torsional oscillations of the upper plate. The flow in the clean fluid region is governed by Navier-Stoke’s equations while in the porous bed the equations are based on Darcy-Lapwood model. The exact solutions of velocity in the clean fluid and the porous medium consist of steady state and transient state. The time required for the transient state to decay is evaluated in detail and ultimate quasi-steady state solution has been derived analytically and also its behaviour is computationally discussed with reference to different flow parameters. The shear stresses on the boundaries and the mass flux are also obtained analytically and their behaviour is computationally discussed.

Unsteady MHD Hartmann - Couette Flow Due to Time Dependent Movement of the Plate of a Darcian Channel with Hall Current and Ion-Slip Effects

Unsteady MHD Hartmann - Couette Flow Due to Time Dependent Movement of the Plate of a Darcian Channel with Hall Current and Ion-Slip Effects

Combined Influence of Hall Current and Soret Effect on Chemically Reacting Magnetomicropolar Fluid Flow from Radiative Rotating Vertical Surface with Variable Suction in Slip-Flow Regime.

An analysis study is presented to study the effects of Hall current and Soret effect on unsteady hydromagnetic natural convection of a micropolar fluid in a rotating frame of reference with slip-flow regime. A uniform magnetic field acts perpendicularly to the porous surface which absorbs the micropolar fluid with variable suction velocity. The effects of heat absorption, chemical reaction, and thermal radiation are discussed and for this Rosseland approximation is used to describe the radiative heat flux in energy equation. The entire system rotates with uniform angular velocity Ω about an axis normal to the plate. The nonlinear coupled partial differential equations are solved by perturbation techniques. In order to get physical insight, the numerical results of translational velocity, microrotation, fluid temperature, and species concentration for different physical parameters entering into the analysis are discussed and explained graphically. Also, the results of the skin-friction coefficient, the couple stress coefficient, Nusselt number, and Sherwood number are discussed with the help of figures for various values of flow pertinent flow parameters.

Effects of Hall Currents and Radiation on Unsteady MHD Flow Past a Heated Moving Vertical Plate

The effects of Hall currents and radiation on MHD flow of a viscous incompressible electrically conducting fluid past a moving vertical plate with variable temperature in the presence of a uniform transverse magnetic field have been studied. The governing equations are solved analytically using the Laplace transform technique. Effects of the physical parameters on the velocity (both primary and secondary) profiles and temperature distribution are shown graphically and the results are discussed.

Hall Effects on Steady MHD Heat and Mass Transfer Free Convection Flow along an Inclined Stretching Sheet with Suction and Heat Generation

The heat and mass transfer of a steady flow of an incompressible electrically conducting fluid over an inclined stretching plate under the influence of an applied uniform magnetic field with heat generation and suction and the effects of Hall current are investigated. Using suitable similarity transformations the governing boundary layer equations for momentum, thermal energy and concentration are reduced to a set of coupled ordinary differential equations which are then solved numerically by the shooting method along with Runge- Kutta fourth-fifth order integration scheme. The numerical results concerned with the velocity, secondary velocity, temperature and concentration profiles effects of various parameters on the flow fields are investigated and presented graphically. The results have possible technological applications in liquid-based systems involving stretchable materials. © 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v6i3.16903 J. Sci. Res. 6 (3), 457-466 (2014)

Hall Current Effect on Visco-elastic Mhd Oscillatory Convective Flow through a Porous Medium in a Vertical Channel with Heat Radiation

field of uniform strength is applied in the direction normal to the planes of the plates. The temperature of one of the plates varies periodically and the temperature difference of the plates is high enough to induce heat transfer due to radiation. A closed form solution of the problem is obtained. The effects of various parameters on the velocity profiles, the skinfriction in terms of the amplitude and the phase angle are shown graphically and discussed in detail.

Nonlinear peristaltic flow of a Carreau fluid in the presence of Hall current and convective effect

Influence of Hall current on the peristaltic transport of an incompressible Carreau fluid in a channel is explored. The mathematical analysis is performed in the presence of convective conditions. A stream function formulation is adopted in the mathematical modelling. Long-wavelength and low-Reynolds-number approximations are utilized. The analysis for stream function, temperature, pressure gradient and pressure rise is performed for small Weissenberg number. Detailed analysis via plots is performed for various emerging parameters.

Heat Transfer on Unsteady MHD Oscillatory Visco-elastic flow through a Porous medium in a Rotating parallel plate channel taking Hall current effects

We consider the unsteady flow of a conducting optically thin visco-elastic fluid through a rotating channel filled with saturated porous medium and non-uniform walls temperature has been discussed taking hall current effects. It is assumed that the fluid has small electrical conductivity and the electromagnetic force produced is very small. The analytical solutions are obtained for the problem making use of perturbation technique. The effects of the radiation and the magnetic field parameters on velocity profile and shear stress for different values of the visco-elastic parameter with the combination of the other flow parameters are illustrated graphically, and physical aspects of the problem are discussed.

Effect of Hall Currents and Variable Fluid Properties on MHD Flow past Stretching Vertical Plate by the Presence of Radiation

This paper investigates the effects of Hall currents and radiation on free-convective steady laminar boundary-layer flow past a semi-infinite vertical plate for large temperature differences. A uniform magnetic field is applied perpendicular to the plate. The fluid density is assumed to vary exponentially and the thermal conducting linearly with temperature. The fluid viscosity is assumed to vary as a reciprocal of a linear function of temperature. The usual Boussinesq approximation is neglected. The nonlinear boundary layer equations governing the problem under consideration are solved numerically by applying an efficient numerical technique based on the shooting method. The effects of the magnetic parameter , the Hall parameter m, the density/temperature parameter n, the radiation parameter N , the thermal conductivity parameter S, the viscosity temperature , and the temperature ratio parameter are examined on the velocity and temperature distribution as well as the coefficient of heat flux and shearing stress at the plate.

Finite element and network electrical simulation of rotating magnetofluid flow in nonlinear porous media with inclined magnetic field and hall currents

A mathematical model is presented for viscous hydromagnetic flow through a hybrid non-Darcy porous media rotating generator. The system is simulated as steady, incompressible flow through a nonlinear porous regime intercalated between parallel plates of the generator in a rotating frame of reference in the presence of a strong, inclined magnetic field A pressure gradient term is included which is a function of the longitudinal coordinate. The general equations for rotating viscous magnetohydrodynamic flow are presented and neglecting convective acceleration effects, the two-dimensional viscous flow equations are derived incorporating current density components, porous media drag effects, Lorentz drag force components and Hall current effects. Using an appropriate group of dimensionless variables, the momentum equations for primary and secondary flow are rendered nondimensional and shown to be controlled by six physical parameters-Hartmann number (Ha), Hall current parameter (Nh), Darcy number (Da), Forchheimer number (Fs), Ekman number (Ek) and dimensionless pressure gradient parameter (Np), in addition to one geometric parameter-the orientation of the applied magnetic field (? ). Several special cases are extracted from the general model, including the non-porous case studied earlier by Ghosh and Pop (2006). A numerical solution is presented to the nonlinear coupled ordinary differential equations using both the Network Simulation Method and Finite Element Method, achieving excellent agreement. Additionally very good agreement is also obtained with the earlier analytical solutions of Ghosh and Pop (2006). for selected Ha, Ek and Nh values. We examine in detail the effects of magnetic field, rotation, Hall current, bulk porous matrix drag, second order porous impedance, pressure gradient and magnetic field inclination on primary and secondary velocity distributions and also frictional shear stresses at the plates. Primary velocity is seen to decrease with an increase in Hall current parameter (Nh) with the converse observed for the secondary velocity.

Hall Effects on unsteady MHD flow of a Non-Newtonian fluid through a Porous medium with uniform suction and injection

In this Paper we discussed the unsteady magneto hydro dynamic flow of an electrically conducting viscous incompressible non-Newtonian Bingham fluid through a porous medium bounded by two parallel non- conducting porous plates with heat transfer considering the hall current effects into account. The fluid is driven by a uniform pressure gradient parallel to the channel plates and the entire flow field is subjected to a uniform magnetic field of strength Ho with the normal to the boundaries in the transverse xz-plane. An external uniform magnetic field is applied perpendicular to the plates and the fluid motion is subjected to a uniform suction and injection. The lower plate is stationary and the upper plate moves with a constant velocity and the two plates are kept at different but constant temperatures. Numerical solutions are obtained for the governing momentum and energy equations taking the Joule and viscous dissipations into consideration. The effects of the Hall term, the parameter describing the non-Newtonian behaviour, and the velocity of suction and injection on both the velocity and temperature distributions is studied.

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.