Influence of magnetic field and Hall currents on blood flow through a stenotic artery

A micropolar model for blood simulating magnetohydrodynamic flow through a horizontally nonsymmetric but vertically symmetric artery with a mild stenosis is presented. To estimate the effect of the stenosis shape, a suitable geometry has been considered such that the horizontal shape of the stenosis can easily be changed just by varying a parameter referred to as the shape parameter. Flow parameters, such as velocity, the resistance to flow （the resistance impedance）, the wall shear stress distribution in the stenotic region, and its magnitude at the maximum height of the stenosis （stenosis throat）, have been computed for different shape parameters, the Hartmann number and the Hall parameter. This shows that the resistance to flow decreases with the increasing values of the parameter determining the stenosis shape and the Hail parameter, while it increases with the increasing Hartmann number. The wall shear stress and the shearing stress on the wall at the maximum height of the stenosis possess an inverse characteristic to the resistance to flow with respect to any given value of the Hartmann number and the Hall parameter. Finally, the effect of the Hartmann number and the Hall parameter on the horizontal velocity is examined.

Time-dependent MHD Couette flow of rotating fluid with Hall and ion-slip currents

The unsteady magnehydrodynamics （MHD） Couette flow of an electrically conducting fluid in a rotating system is investigated by taking the Hall and ion-slip currents into consideration. The derived fundamental equations on the assumption of a small magnetic Reynolds number are solved analytically with the well-known Laplace transform technique. The unified closed-form expressions axe obtained for the velocity and the skin friction in the two different cases of the magnetic field being fixed to either the fluid or the moving plate. The effects of various parameters on the velocity and the skin friction axe discussed by graphs. The results reveal that the primary and secondary velocities increase with the Hall current. An increase in the ion-slip paxameter also leads to an increase in the primary velocity but a decrease in the secondary velocity. It is also shown that the combined effect of the rotation, Hall, and ion-slip parameters determines the contribution of the secondary motion in the fluid flow.

Numerical and analytical investigations of thermosolutal instability in rotating Rivlin-Ericksen fluid in porous medium with Hall current

Numerical and analytical investigations of the thermosolutal instability in a viscoelastic Rivlin-Ericksen fluid are carried out in the presence of a uniform vertical magnetic field to include the Hall current with a uniform angular velocity in a porous medium. For stationary convection, the stable solute gradient parameter and the rota- tion have stabilizing effects on the system, whereas the magnetic field and the medium permeability have stabilizing or destabilizing effects on the system under certain condi- tions. The Hall current in the presence of rotation has stabilizing effects for sufficiently large Taylor numbers, whereas in the absence of rotation, the Hall current always has destabilizing effects. These effects have also been shown graphically. The viscoelastic effects disappear for stationary convection. The stable solute parameter, the rotation, the medium permeability, the magnetic field parameter, the Hall current, and the vis- coelasticity introduce oscillatory modes into the system, which are non-existent in their absence. The sufficient conditions for the non-existence of overstability are also obtained.

Finite element solution of heat and mass transfer flow with Hall current,heat source,and viscous dissipation

The aim of the paper is to investigate the effect of heat and mass transfer on the unsteady magnetohydrodynamic free convective flow with Hall current, heat source, and viscous dissipation. The problem is governed by the system of coupled non-linear partial differential equations whose exact solution is difficult to obtain. Therefore, the problem is solved by using the Galerkin finite element method. The effects of the various parameters like Hall current, Eckert number, heat source parameter, Prandtl number, and Schmidt number on the velocity components, the temperature, and the concentration are also examined through graphs.

Effect of Hall current on MHD natural convection flow from vertical permeable flat plate with uniform surface heat flux

The effect of the Hall current on the magnetohydrodynamic （MHD） natural convection flow from a vertical permeable flat plate with a uniform heat flux is analyzed in the presence of a transverse magnetic field.It is assumed that the induced magnetic field is negligible compared with the imposed magnetic field.The boundary layer equations are reduced to a suitable form by employing the free variable formulation （FVF） and the stream function formulation （SFF）.The parabolic equations obtained from FVF are numerically integrated with the help of a straightforward finite difference method.Moreover,the nonsimilar system of equations obtained from SFF is solved by using a local nonsimilarity method,for the whole range of the local transpiration parameter ζ.Consideration is also given to the regions where the local transpiration parameter ζ is small or large enough.However,in these particular regions,solutions are acquired with the aid of a regular perturbation method.The effects of the magnetic field M and the Hall parameter m on the local skin friction coefficient and the local Nusselt number coefficient are graphically shown for smaller values of the Prandtl number P r （= 0.005,0.01,0.05）.Furthermore,the velocity and temperature profiles are also drawn from various values of the local transpiration parameter ζ.

Interfacial spin Hall current in a Josephson junction with Rashba spin-orbit coupling

We theoretically investigate the spin transport properties of the Cooper pairs in a conventional Josephson junction with Rashba spin-orbit coupling considered in one of the superconducting leads.It is found that an angle-resolved spin supercurrent flows through the junction and a nonzero interfacial spin Hall current driven by the superconducting phase difference also appears at the interface.The physical origin of this is that the Rashba spin-orbit coupling can induce a triplet order parameter in the s-wave superconductor.The interfacial spin Hall current dependences on the system parameters are also discussed.

Investigation of the Effects of Some Physical Parameters and Hall Current on MHD Fluid Flow with Heat Flux over a Porous Medium

In this paper, an investigation of the effects of some physical parameters and Hall current on magneto hydrodynamics (MHD) fluid flow with heat flux over a porous medium was carefully examined, taking into consideration Hall effects where the temperature and concentration are assumed to be oscillating with time. Furthermore, perturbation method is used in solving the governing equations. The profiles of velocity, temperature and concentration are presented graphically, going into the problem the primary and secondary velocity are presented and compute for some physical parameters such as mass Grashof number (Gc), Schmidt number Sc, Prandtl number (Pr) viscoelastic parameter (K1) and hall current parameter (m). Results indicated that primary velocity increases with increase in values of Gc on one hand and on the other hand it decreases with increase in the values of Pr, K1 and m. Secondary velocity demonstrated opposite trend.

Soret and Dufour Effects on Unsteady Free Convection Fluid Flow in the Presence of Hall Current and Heat Flux

Unsteady MHD natural convective heat and mass transfer flow through a semi-infinite vertical porous plate in a rotating system have been investigated with the combined Soret and Dufour effects in the presence of Hall current and constant heat flux. It is considered that the porous plate is subjected to constant heat flux. The obtained non-dimensional, non-similar coupled non-linear and partial differential equations have been solved by explicit finite difference technique. Numerical solutions for velocities, temperature and concentration distributions are obtained for various parameters by the above mentioned technique. The local and average shear stresses, Nusselt number as well as Sherwood number are also investigated. The stability conditions and convergence criteria of the explicit finite difference scheme are established for finding the restriction of the values of various parameters to get more accuracy. The obtained results are illustrated with the help of graphs to observe the effects of various legitimate parameters.

Electro-magneto-hydrodynamic flow of couple stress nanofluids in micro-peristaltic channel with slip and convective conditions

This study explores the effects of electro-magneto-hydrodynamics,Hall currents,and convective and slip boundary conditions on the peristaltic propulsion of nanofluids(considered as couple stress nanofluids)through porous symmetric microchannels.The phenomena of energy and mass transfer are considered under thermal radiation and heat source/sink.The governing equations are modeled and non-dimensionalized under appropriate dimensionless quantities.The resulting system is solved numerically with MATHEMATICA(with an in-built function,namely the Runge-Kutta scheme).Graphical results are presented for various fluid flow quantities,such as the velocity,the nanoparticle temperature,the nanoparticle concentration,the skin friction,the nanoparticle heat transfer coefficient,the nanoparticle concentration coefficient,and the trapping phenomena.The results indicate that the nanoparticle heat transfer coefficient is enhanced for the larger values of thermophoresis parameters.Furthermore,an intriguing phenomenon is observed in trapping:the trapped bolus is expanded with an increase in the Hartmann number.However,the bolus size decreases with the increasing values of both the Darcy number and the electroosmotic parameter.

Slip flow of micropolar fluid through a permeable wedge due to the effects of chemical reaction and heat source/sink with Hall and ionslip currents:an analytic approach

This study focuses on the combined impact of heat source/sink and chemical reaction on slip flow of micropolar fluid through a permeable wedge in the existence of Hall and ion-slip currents.The governing highly non-lincar PDEs were altered into a set of non-linear coupled ODEs by using similarity transformations.Differential transformation method(DTM)has been implemented in transformed ODEs equations.The comparison with previous literatures was performed and the data of this study was found to be in accordance with each other.The analytical solutions for skin-friction coefficients(surface drag forces),Nussclt and Sherwood numbers are depicted through graphs and tables.The study of boundary layer flow over a wedge surface plays an imperative role in the field of aerodynamics,heat exchanger,ground water pollution and geothermal system etc.

Interplay of conducting and non-conducting walls on hydromagnetic natural convection flow in a vertical micro-channel with Hall current

Theoretical investigation on the interaction between conducting and nonconducting walls on hydromagnetic natural convection flow of viscous incompressible and electrically conducting fluid through a vertical micro-channel taking into account the effects of induced magnetic field in presence of Hall current is presented.Governing coupled equations responsible for the flow are obtained when either the micro-channel walls are electrically conducting or are electrically non-conducting.Using the method of undetermined coefficients,exact solution are obtained and presented in dimensionless form subject to relevant boundary conditions.Expressions for fluid velocity,induced magnetic field,skin friction,volume flow rate and induced current density in both primary and secondary flow directions are also obtained.Effects of some governing parameters like Hall current parameter,rarefaction parameter and Hartmann number on the different flow situations are given using the aid of line graphs and Tables.The main conclusion of the present analysis is that,in the existence of rarefaction parameter,primary fluid velocity could be enhanced with the increase in Hall parameter when the micro-channel walls are either insulated or when the left micro-channel wall is electrically conducting.Results obtained in this work are relevant in many magnetically controlled devices and could also be used as a benchmark in checking the accuracies of result obtained in some empirical experiments.

Simultaneous effects of Hall current and thermal deposition in peristaltic transport of Eyring-Powell fluid

Peristaltic flow by a sinusoidal traveling wave in the walls of two-dimensional channel with wall properties is investigated. The channel is filled with incompressible Eyring-Powell fluid. Mathematical modeling is developed through aspects of Hall current, thermal deposition and convection. Long wavelength and low Reynolds number considerations are adopted. Perturbation solutions to the resulting problem for small material parameter of fluid are obtained. Expressions of velocity, temperature, concentration and stream function are derived. Variations of pertinent parameters on the physical quantities of interest are explored in detail. The present analysis is especially important to predict the rheological characteristics in engineering applications by peristalsis.

Variable viscosity effects on the flow of MHD hybrid nanofluid containing dust particles over a needle with Hall current——a Xue model exploration

This study scrutinizes the flow of engine oil-based suspended carbon nanotubes magnetohydrodynamics(MHD)hybrid nanofluid with dust particles over a thin moving needle following the Xue model.The analysis also incorporates the effects of variable viscosity with Hall current.For heat transfer analysis,the effects of the Cattaneo–Christov theory and heat generation/absorption with thermal slip are integrated into the temperature equation.The Tiwari–Das nanofluid model is used to develop the envisioned mathematical model.Using similarity transformation,the governing equations for the flow are translated into ordinary differential equations.The bvp4c method based on Runge–Kutta is used,along with a shooting approach.Graphs are used to examine and depict the consequences of significant parameters on involved profiles.The results revealed that the temperature of the fluid and boundary layer thickness is diminished as the solid volume fraction is raised.Also,with an enhancement in the variable viscosity parameter,the velocity distribution becomes more pronounced.The results are substantiated by assessing them with an available study.

Finite element analysis on transient magnetohydrodynamic(MHD)free convective chemically reacting micropolar fluid flow past a vertical porous plate with Hall current and viscous dissipation

This article deals with boundary layer analysis of magnetohydrodynamics on an unsteady chemically reactive micropolar rotating fluid flow past a semi-infinite vertical plate with been developed under Boussinesq approximation.The governing partial differential equations are transformed into a set of coupled partial differential equations using suitable dimensionless quantities.The resultant equations are solved numerically using variational finite element method.A parametric study illustrating the influence of different pertinent parameters is performed and the numerical results for translational velocity,microrotation velocity,temperature and concentration distributions near the boundary layers are discussed and presented graphically for the parametric variations.Finally,the skin-friction,wall couple stress,surface heat transfer and mass transfer rate dependency on the emerging thermo-physical parameters are also tabulated.The finite element code is benchmarked with the results reported in the literature to check the validity and accuracy under some limiting cases and excellent agreement with published solutions is achieved.