scholarly journals Thermal diffusion in a binary fluid mixture flows due to a rotating disc of uniform high suction in presence of a weak axial magnetic field

2010 ◽  
Vol 37 (3) ◽  
pp. 161-187
Author(s):  
B.R. Sharma ◽  
R.N. Singh
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Rotating Disc ◽  
Fluid Mixture ◽  
Suction Parameter ◽  
Electrically Conducting ◽  
Flow Parameters ◽  
Polar Coordinate ◽  
Dimensional Parameters ◽  
High Suction

The effect of a weak uniform axial magnetic field on separation of a binary mixture of incompressible viscous thermally and electrically conducting fluids flowing due to a rotating disc of uniform high suction is examined. Neglecting the induced electric field the equations governing the motion, temperature and concentration are solved in cylindrical polar coordinate by expanding the flow parameters as well as the temperature and the concentration in powers of suction parameter. The solution obtained for concentration distribution is plotted against the different axial distances from the disc for various values of non-dimensional parameters. It is found that the temperature gradient, axial magnetic field, Reynolds number, Schmidt number, Prandtl number and suction parameter effect the species separation significantly.

Magnetohydrodynamic lubrication flow between parallel rotating disks

1962 ◽  
Vol 13 (1) ◽  
pp. 21-32 ◽  
Author(s):  
W. F. Hughes ◽  
R. A. Elco
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Load Capacity ◽  
Electrical Energy ◽  
Axial Current ◽  
Frictional Torque ◽  
Rotating Disks ◽  
Radial Magnetic Field ◽  
Electrically Conducting ◽  
Parallel Disks

The motion of an electrically conducting, incompressible, viscous fluid in the presence of a magnetic field is analyzed for flow between two parallel disks, one of which rotates at a constant angular velocity. The specific application to liquid metal lubrication in thrust bearings is considered. The two field configurations discussed are: an axial magnetic field with a radial current and a radial magnetic field with an axial current. It is shown that the load capacity of the bearing is dependent on the MHD interactions in the fluid and that the frictional torque on the rotor can be made zero for both field configurations by supplying electrical energy through the electrodes to the fluid.

Stability of the Base Flow to Axisymmetric and Plane-Polar Disturbances in an Electrically Driven Flow Between Infinitely-Long, Concentric Cylinders

2000 ◽  
Vol 123 (1) ◽  
pp. 31-42
Author(s):  
J. Liu ◽  
G. Talmage ◽  
J. S. Walker
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Axial Magnetic Field ◽  
Normal Modes ◽  
Azimuthal Velocity ◽  
Base Flow ◽  
Transition To Turbulence ◽  
Electrically Conducting ◽  
Concentric Cylinders ◽  
The Stability

The method of normal modes is used to examine the stability of an azimuthal base flow to both axisymmetric and plane-polar disturbances for an electrically conducting fluid confined between stationary, concentric, infinitely-long cylinders. An electric potential difference exists between the two cylinder walls and drives a radial electric current. Without a magnetic field, this flow remains stationary. However, if an axial magnetic field is applied, then the interaction between the radial electric current and the magnetic field gives rise to an azimuthal electromagnetic body force which drives an azimuthal velocity. Infinitesimal axisymmetric disturbances lead to an instability in the base flow. Infinitesimal plane-polar disturbances do not appear to destabilize the base flow until shear-flow transition to turbulence.

Effects of Mixed Convection on the Oscillatory Flow of a Couple Stress Fluid through a Vertical Plate with Variable Fluid Properties

2018 ◽  
Vol 388 ◽  
pp. 328-343
Author(s):  
R. Suresh Babu ◽  
B. Rushi Kumar ◽  
P.A. Dinesh
Keyword(s):  
Magnetic Field ◽  
Couple Stress ◽  
Vertical Plate ◽  
Couple Stress Fluid ◽  
Electrically Conducting ◽  
Coupled Equations ◽  
Variable Permeability ◽  
Variable Fluid Properties ◽  
Fluid Properties ◽  
Dimensional Parameters

A numerical computation has been carriedout for the steady, mixed convective, incompressible, viscous, electrically conducting couple stress fluid through a vertical plate with variable fluid properties in a porous medium. A uniform magnetic field is applied in the transverse direction and parallel to the vertical plate of the physical model and governing equations are derived for it."Using a suitable similarity transformation, governed PDE's are transformed into a set of ODE's which are highly non-linear coupled equations. An advanced Shooting technique is adopted to compute the variations of velocity, temperature, concentration in terms of non-dimensional parameters. Also physical interpretation of non-dimensional parameters like couple stress parameter magnetic field Prandtl number Schmidt number thermal conductivity and solutal diffusivity parameters are examined through plots for both variable permeability and uniform permeability."From the numerical results, an excellent agreement has been observed for the present results, as well as comparison is made between the present and the earlier works for a particular case of the problem.

THE STAEILITY OF COUETTE FLOW IN AN AXIAL MAGNETIC FIELD

1958 ◽  
Vol 36 (11) ◽  
pp. 1509-1525 ◽  
Author(s):  
E. R. Niblett
Keyword(s):  
Magnetic Field ◽  
Boundary Conditions ◽  
Theoretical Prediction ◽  
Viscous Flow ◽  
Rotation Speed ◽  
Axial Magnetic Field ◽  
Radioactive Isotopes ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
The Stability

Chandrasekhar's theory of the stability of viscous flow of an electrically conducting fluid between coaxial rotating cylinders with perfectly conducting walls is extended to include the case of non-conducting walls, and it is found that their effect is to reduce the critical Taylor numbers and increase the wavelength of the instability patterns by considerable amounts. An experiment designed to measure the values of magnetic field and rotation speed at the onset of instability in mercury between perspex cylinders is described. The radioactive isotopes Hg197 and Hg203 were used to trace the flow. The results support the theoretical prediction that the boundary conditions can have a large effect on the motion.

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

2014 ◽  
Vol 11 (2) ◽  
pp. 147-156 ◽  
Author(s):  
M.C Raju ◽  
S.V.K Varma
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Fluid Flow ◽  
Newtonian Fluid ◽  
Porous Plate ◽  
Sink Strength ◽  
Suction Parameter ◽  
Electrically Conducting ◽  
Highly Nonlinear ◽  
Constant Suction

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

Unsteady Hydromagnetic Radiative Flow of a Dusty Fluid Past a Porous Plate With Ramped Wall Temperature

2013 ◽  
Author(s):  
R. Nandkeolyar ◽  
P. Sibanda ◽  
Md. S. Ansari
Keyword(s):  
Magnetic Field ◽  
Laplace Transform ◽  
Porous Plate ◽  
Inverse Laplace Transform ◽  
Combined Effects ◽  
Dusty Fluid ◽  
Electrically Conducting ◽  
Flow Parameters ◽  
Energy Transfers ◽  
Laplace Transform Technique

The combined effects of applied magnetic field, thermal radiation and suction on the flow and free convective heat transfer of a viscous, incompressible, electrically conducting dusty fluid past a flat plate with ramped temperature are studied. The governing partial differential equations for momentum and energy transfers, for both the fluid and particle phases, are solved using Laplace transform technique. The inverse Laplace transform is obtained numerically using Matlab. A comparison of Numerical solution and analytical solution for energy transfer is made which shows an excellent agreement. The effects of pertinent flow parameters are analyzed with the help of graphs and tables.

Effect of an Inclined Magnetic Field on the Flow of Nanofluids in a Tapered Asymmetric Porous Channel with Heat Source/Sink and Chemical Reaction

2017 ◽  
Vol 1 (2) ◽  
pp. 104 ◽  
Author(s):  
Ajaz Ahmad Dar
Keyword(s):  
Magnetic Field ◽  
Heat Source ◽  
Chemical Reaction ◽  
Wave Length ◽  
Porous Channel ◽  
Inclined Magnetic Field ◽  
Electrically Conducting ◽  
Flow Parameters ◽  
Channel Effect ◽  
Source Sink

<p><em>This article deals with the effect of an inclined magnetic field with heat source/sink on the flow of nanofluids in a tapered asymmetric porous channel. Effect of chemical reaction has been taken into account. The blood is considered as an incompressible electrically conducting viscous fluid. The assumption of low Reynolds number and long wave length approximations has been adopted. Exact solutions for dimensionless axial velocity, concentration and temperature profile are obtained analytically. The obtained results are displayed and discussed in detail with the help of graphs for the variation of different emerging flow parameters.</em></p>

Hydromagnetic spin-up of a fluid confined by two flat electrically conducting boundaries

1971 ◽  
Vol 50 (3) ◽  
pp. 609-623 ◽  
Author(s):  
David E. Loper
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Arbitrary Field ◽  
Plate Interface ◽  
Magnetic Diffusion ◽  
Electrically Conducting ◽  
Single Plate ◽  
Electrically Conducting Fluid ◽  
Special Cases ◽  
Plate Analysis

The prototype linear spin-up problem consisting of a homogeneous viscous electrically conducting fluid confined between two infinite flat rotating electrically conducting plates in the presence of an applied axial magnetic field is studied in an effort to understand better the strength and nature of the coupling between a fluid and its rotating conducting container. It is assumed that the response time of the bounding plates to a magnetic perturbation is much less than the fluid spin-up time and that the plate conductivity is an arbitrary function of distance from the fluid-plate interface. The general Laplace transform solution is inverted and discussed for three special cases: magnetic diffusion regions thick compared with fluid depth during spin-up, arbitrary magnetic field strength and boundary conductance; magnetic diffusion regions thin, weak conductance, arbitrary field; magnetic diffusion regions thin, strong conductance, arbitrary field. In each case conductance of the boundary strengthens the coupling between fluid and boundary, thereby decreasing the spin-up time. The corresponding single plate analysis of Loper (1970a) is found to predict spin-up accurately only if the boundary conductance is much smaller than that of the fluid. The fluid possesses an oscillatory mode of spin-up if the magnetic diffusion regions are thin and boundary conductance is large. That is, the inviscid current-free core of fluid rotates significantly faster than the boundaries during a portion of the spin-up process.

scholarly journals Global stability of the rotating-disc boundary layer with an axial magnetic field

2013 ◽  
Vol 724 ◽  
pp. 510-526 ◽  
Author(s):  
Christian Thomas ◽  
Christopher Davies
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Linear Stability ◽  
Axial Magnetic Field ◽  
Numerical Study ◽  
Control Strategies ◽  
Base Flow ◽  
Global Instability ◽  
Rotating Disc ◽  
Radially Inhomogeneous

AbstractA numerical study is conducted to investigate the influence of a uniform axial magnetic field on the global linear stability of the rotating-disc boundary layer. Simulation results obtained using a radially homogenized base flow were found to be in excellent agreement with an earlier linear stability analysis, which indicated that an axial magnetic field can locally suppress both convective and absolute instabilities. However, the numerical results obtained for the genuine, radially inhomogeneous, flow indicate that a global form of instability develops for sufficiently large magnetic fields. The qualitative nature of the global instability is similar to that which was observed in a previous study, where mass suction was applied at the rotating disc surface. It is shown that, just as for the case with mass suction, it is possible to explain the promotion of global instability by considering a model that includes detuning effects, which are associated with the radial variation of locally defined absolute temporal frequencies. The recurrence of the same type of instability behaviour when two distinct flow control strategies are implemented, one using suction and the other an axial magnetic field, indicates that the phenomena described by the model may be considered generic.

scholarly journals Separation of species of a binary fluid mixture confined in a channel in presence of a strong transverse magnetic field

2012 ◽  
Vol 66 (2) ◽  
pp. 171-180
Author(s):  
Bishwaram Sharma ◽  
Niroj Sing ◽  
Rupam Gogoi ◽  
Kabita Nath
Keyword(s):  
Magnetic Field ◽  
Transverse Magnetic Field ◽  
Transverse Magnetic ◽  
Magnetic Reynolds Number ◽  
Parallel Plates ◽  
Separation Processes ◽  
Fluid Mixture ◽  
Electrically Conducting ◽  
Basic Fluid ◽  
Cartesian Coordinate

Effects of a transverse magnetic field on separation of a binary mixture of incompressible viscous thermally and electrically conducting fluids confined between two stationary parallel plates are examined. Both the plates are maintained at constant temperatures. It is assumed that one of the components, which is rarer and lighter, is present in the mixture in a very small quantity. The equations governing the motion, temperature and concentration in Cartesian coordinate are solved analytically. The solution obtained for concentration distribution is plotted against the width of the channel for various values of non-dimensional parameters. It is found that the effect of transverse magnetic field is to separate the species of rarer and lighter component by contributing its effect directly to the temperature gradient and the pressure gradient. The effects of increase in the values of Hartmann number, magnetic Reynolds number, barodiffusion number, thermal diffusion number, electric field parameter and the product of Prandtl number and Eckert number are to collect the rarer and lighter component near the upper plate and throw away the heavier component towards the lower plate. The problem discussed here derives its application in the basic fluid dynamics separation processes to separate the rare component of the different isotopes of heavier molecules where electromagnetic method of separation does not work.

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