Hall effects on MHD free-convection flow past an accelerated vertical porous plate

The effect of Hall currents on the hydromagnetic free-convection flow of an electrically conducting and incompressible viscous fluid past a uniformly accelerated infinite vertical porous plate is discussed. The magnetic Reynolds number is assumed to be small so that the induced magnetic field can be neglected. The governing equations of the flow are solved by defining a complex velocity with the help of the Laplace transform method when the Prandtl number is equal to unity. The influence of the various parameters on the unsteady flow field is presented for both the cases, cooling and heating of the porous plate by free-convection currents.     

Photometry of the fast-rotating late-type star W92 in NGC 2264

The effect of a uniform transverse magnetic field on the free-convection flow of an electrically conducting fluid past a uniformly accelerated infinite vertical porous plate is discussed. Finite-difference method has been used to obtain the solution of the governing equations when the Prandtl number is not equal to unity. The velocity profiles have been shown graphically for both cases, cooling and heating of the porous plate. The numerical values of the skin-friction are entered in table and the effects of the various parameter are discussed on the flow field.     

Hall effects on an oscillatory MHD flow in the Stokes problem past an infinite vertical porous plate,I

Hall effects on the hydromagnetic free convection flow of an electrically conducting incompressible viscous fluid past a steadily moving vertical porous plate has been analysed when the free stream oscillates in magnitude. The flow is subjected to a constant suction, through the porous plate, and the difference between wall temperature and the free-stream is moderately large causing the free convection currents. The mathematical analysis is presented for the hydromagnetic boundary layer flow without taking into account the induced magnetic field. This is a valid assumption for small magnetic Reynolds number. Approximate solutions for the components of velocity field and temperature field and their related quantities are obtained. The influence of various parameters entering into the problem is extensively discussed with the help of graphs and tables.     

MHD free-convection flow in the stokes problem for a porous vertical plate by finite difference method

The flow past an infinite vertical isothermal plate started impulsively in its own plane in a viscous incompressible and electrically conducting fluid has been considered. The magnetic Reynolds number is assumed small so that the induced magnetic field can be neglected. The governing equations of the flow are solved by finite-difference method when the Prandtl number is not equal to unity. The influence of the various parameters, entering into the problem, on the velocity field, the temperature field and on their related quantities is extensively discussed with the help of graphs and tables.     

MHD free-convection and mass-transform flow through a porous medium

The effect of a uniform transverse magnetic field on the free-convection and mass-transform flow of an electrically-conducting fluid past an infinite vertical plate for uniformly accelerated motion of the plate through a porous medium is discussed. The magnetic lines of force are assumed to be fixed relative to the plate. Expression for the velocity field and skin-friction are obtained by the Laplace transform technique. The influence of the various parameters, entering into the problem, on the velocity field and skin-friction is extensively discussed.     

Unsteady hydromagnetic rotating flow near an oscillating plate

The three-dimensional flow of a viscous incompressible electrically conducting fluid near an infinite plate (or wall) of non-conductor, which is oscillating harmonically in a uniform rotating medium, is studied in the presence of a uniform magnetic field. The impressed uniform magnetic field is perpendicular to the plate and the induced magnetic field is considered. Exact solution of this problem is obtained for the velocity and magnetic fields. Neglecting the induced magnetic field we readily obtain the results of all the previous investigations. The effects of the rotation and the magnetic field are comparable with one another and are discussed for the whole problem. Also, the drag and the lateral stress on the plate are discussed.     

MHD free-convection and mass transfer flow of an elasto-viscous fluid

The effects of magnetic field and mass transfer on the flow of an elasto-viscous fluid past an infinite vertical plate, when the plate is moving with uniform velocityU, are discussed. The magnetic lines of force are assumed to be fixed relative to the plate. The Laplace transform method is used to obtain the expression for velocity. The effect of various parameters, occurring into the problem, is discussed with the help of tables.     

MHD free-convection flow in the stokes problem for a porous vertical plate

The effect of a uniform transverse magnetic field on the free-convection flow of an electrically-conducting fluid past an infinite, vertical, porous plate for both classes of impulsive as well as uniformly-accelerated motion of the plate is discussed. The magnetic lines of force are assumed to be fixed relative to the plate. Expressions for the velocity field and skin friction for both cases are obtained by the Laplace transform technique. The influence of the various parameters, entering into the problem, on the velocity field and skin-friction is extensively discussed with the help of graphs and tables.     

MHD oscillatory flow past a vertical porous plate through porous medium in the presence of thermal and mass diffusion with constant heat source

Effects of temperature-dependent heat source on hydromagnetic free-convection flow (set up due to temperature as well as species concentration) of an electrically-conducting incompressible viscous fluid past a steadily moving vertical porous plate through high porous medium has been analysed when the free stream oscillates in magnitude. The flow is subjected to a constant suction, through the porous plate. The mathematical analysis is presented for the hydromagnetic flow without taking into account the induced magnetic field. This is a valid assumption for small magnemtic Reynold number. Approximate analysis for the velocity and temperature field and their related quantities are obtained. The influence of various parameters entering into the problem is extensively discussed with the help of graphs and tables.     

Free convection effects on oscillatory hydromagnetic boundary layer flow

Unsteady flow of an incompressible, viscous, electrically conducting fluid past an infinite porous plate has been analysed under the following assumptions: (i) suction velocity oscillates in time about a constant mean, (ii) the free-stream velocity oscillates in time about a constant mean, (iii) the plate temperature is constant, (iv) the difference between the temperature of the plate and the free-stream is moderately large causing the free-convection currents, (v) a uniform transverse magnetic field is applied, (vi) the magnetic Reynolds number is very small and hence the induced magnetic field is neglected. Approximate solutions to the coupled non-linear equations governing the flow are derived for the transient velocity, the transient temperature, the amplitude and the phase of the skin-friction and the rate of heat transfer. During the course of analysis the effects of ±G (Grashof number),P (Prandtl number),M (magnetic field parameter),A (suction parameter) and ω (frequency) are discussed.     

MHD free-convection flow in the stokes problem for a vertical porous plate in a rotating system

The flow past an infinite vertical isothermal plate started impulsively in its own plane in a viscous incompressible and electricalfy conducting fluid has been presented in a rotating system. The magnetic Reynolds number is assumed small so that the induced magnetic field can be neglected. The governing equations of the flow are solved by defining a complex variable with the help of the Laplace transform technique. The influence of the various parameters, occurring into the problem, on the axial and transverse components of the velocity and skin-friction is extensively discussed with the help of graphs and table.     

Hydromagnetic unsteady flow due to an unsteady plate

The unsteady flow near an infinite flat plate, which is oscillating harmonically in its own plane, is studied in the presence of a magnetic field subjected to suction or injection. The magnetic field is perpendicular to the plate and the flow of viscous incompressible and electrically conducting fluid is regarded as being initially at rest. Exact solutions for velocity and skin-friction are obtained for the magnetic field fixed to the fluid or to the plate.     

Oscillatory hydromagnetic free-convection flow in the stokes problem past an infinite vertical porous plate in a rotating system,I

Rotation effect on the hydromagnetic free-convection flow of an electrically conducting, viscous, and incompressible fluid past a steadily moving vertical porous plate has been analysed in the presence of a transverse magnetic field. The free-stream velocity oscillates in time about a constant mean, while the suction velocity, normal to the porous plate, is constant. The magnetic Reynolds number of the flow is taken small enough so that the induced magnetic field can be neglected. The plate temperature is constant and the difference between the temperature of the plate and the free stream is moderately large causing the free-convection currents. The flow field is described by nonlinar coupled system of equations. With viscous dissipative heat taken into account, approximate solutions of the problem are obtained for the components of velocity field and temperature field as well as for the skin-friction components and rate of heat transfer.     

Hydromagnetic free-convection flow near a time-varying accelerated vertical plate

The effect of a uniform transverse magnetic field on the free-convection flow of an electrically conducting fluid past an exponentially accelerated infinite vertical plate is analysed for both cases, when the magnetic lines of force are fixed relative to the fluid and the plate, respectively. The Laplace transform method is used to obtain the expressions for velocity and skin-friction. The effect of a magnetic parameter is to decrease the velocity of water when the magnetic field is fixed to the fluid, while it increases the velocity field when the magnetic lines of force are fixed relative to the plate.     

Unsteady magnetic boundary-layer flow of power-law non-Newtonian conducting fluid through a porous medium past an infinite porous flat plate

In this paper, the nonsteady flow of non-Newtonian power-law conducting fluid through a porous medium past an infinite porous plate is investigated. The system is stressed by a constant transverse magnetic field. The velocity outside the boundary layer depends exponentially on time. The rheological effects are shown and discussed on the shear stress in terms of rheological parameter of power-law fluid. The approximate solution in a closed form were obtained by using the Galerkin method. Also the effect of the magnetic field and permeability parameter are discussed.     

The effects of induced magnetic field on unsteady hydromagnetic flows in a rotating medium

Unsteady flows of a viscous incompressible electrically conducting fluid filling the semi-infinite space in contact with an infinite conducting plate in a rotating medium in the presence of a transverse induced magnetic field are investigated under an arbitrary time-dependent forcing effect on the motion of the plate where the plate and the fluid rotate uniformly as a rigid body. By using the Laplace transform technique, the Greens function of the problem is determined and certain asymptotic expansions of the exact solutions are analyzed. the steady-state oscillatory flow problem is solved, and structure of waves and displacement thickness of the boundary layers are discussed for different cases of some natural parameters in the problem. The results are compared with similar flows in the presence of a constant magnetic field.     

A class of exact solutions of the unsteady magnetohydrodynamic free-convection flows

The unsteady free-convection flow of an electrically-conducting fluid near a moving vertical plate of infinite extent is investigated in the presence of uniform transverse magnetic field fixed to the fluid or to the plate. Exact solution of this problem is obtained with the aid of the Laplace transform technique, when the plate is moving with a velocity which is an arbitrary functiuon of time. The solution is exemplified for three particular cases of physical interest; the non-magnetic case is also discussed.     

MHD thermal-diffusion effects on free-convective and mass-transfer flow over an infinite vertical moving plate

The Soret effect on MHD free-convective and mass-transfer flow of an incompressible, viscous, and electrically-conducting fluid, past a moving vertical infinite plate is studied. The flow is assumed to be at small Reynolds numbers so that the induced magnetic field is neglected. The problem is solved with the help of the Laplace transform method for two different values of the dimensionless functionf(t) signifying two different cases, e.g., (i) when the boundary surface, the flat plate, is impulsively started, moving in its own plane (I.S.P.) and (ii) when it is uniformly accelerated (U.A.P.). The effects on the velocity field as well as on the skin-friction of the various dimensionless parameters occurring into the problem, especially the magnetic parameterM and Soret number So, are discussed with the help of graphs.     

Influence of viscous dissipation on a hydromagnetic field

The effect of a transverse magnetic field and of the viscosity diffusion on the free-convection flow of an electrically-conducting incompressible fluid past a uniformally accelerated vertical plate is discussed. A finite difference method has been used to obtain a numerical solution. The influence of the various parameters on the flow field is discussed.     

A numerical study of the unsteady MHD free convection with hall current

Effect of Hall current on the hydromagnetic free-convection flow of an electrically-conducting viscous incompressible fluid past an impulsively accelerated vertical porous plate in the presence of a uniform transverse magnetic field subjected to a constant transpiration velocity is analyzed for the case of small magnetic Reynolds number. Numberical solutions are obtained for the axial and transverse components of the velocity as well as the skin-friction by employing the Crank-Nicolson implicit finite-difference method for all probable values of the Prandtl number. The results are discussed with the effects of the Grashof number Gr, the transpiration velocity parameter , the Hall current parameterm, and the magnetic field parameterM for the Prandtl number Pr=0.71 which represents air at 20° C.