Reverse Flow in Magnetoconvection of Two Immiscible Fluids in a Vertical Channel

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Alessandra Borrelli ◽  
Giulia Giantesio ◽  
Maria Cristina Patria
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Mixed Convection ◽  
Newtonian Fluid ◽  
Hartmann Number ◽  
Reverse Flow ◽  
Vertical Channel ◽  
Boussinesq Approximation ◽  
Immiscible Fluids ◽  
Induced Magnetic Field

This paper concerns the study of the influence of an external magnetic field on the reverse flow occurring in the steady mixed convection of two Newtonian immiscible fluids filling a vertical channel under the Oberbeck–Boussinesq approximation. The two isothermal boundaries are kept either at different or at equal temperatures. The velocity, the temperature, and the induced magnetic field are obtained analytically. The results are presented graphically and discussed for various values of the parameters involved in the problem (in particular, the Hartmann number and the buoyancy coefficient) and are compared with those for a single Newtonian fluid. The occurrence of the reverse flow is explained and carefully studied.

scholarly journals Magnetohydrodynamic Flow of a Bingham Fluid in a Vertical Channel: Mixed Convection

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 154
Author(s):  
Alessandra Borrelli ◽  
Giulia Giantesio ◽  
Maria Cristina Patria
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Reverse Flow ◽  
Vertical Channel ◽  
Bingham Fluid ◽  
Induced Magnetic Field ◽  
Bingham Number ◽  
External Uniform Magnetic Field

In this paper, we describe our study of the mixed convection of a Boussinesquian Bingham fluid in a vertical channel in the absence and presence of an external uniform magnetic field normal to the walls. The velocity, the induced magnetic field, and the temperature are analytically obtained. A detailed analysis is conducted to determine the plug regions in relation to the values of the Bingham number, the buoyancy parameter, and the Hartmann number. In particular, the velocity decreases as the Bingham number increases. Detailed considerations are drawn for the occurrence of the reverse flow phenomenon. Moreover, a selected set of diagrams illustrating the influence of various parameters involved in the problem is presented and discussed.

scholarly journals Dual Solutions in Mixed Convection Stagnation-Point Flow Over a Vertical Stretching Sheet with External Magnetic Field and Radiation Effect

2021 ◽  
Vol 80 (2) ◽  
pp. 22-32
Author(s):  
Fadzilah Md Ali ◽  
Amira Natasya Azizan Khamat ◽  
Mohamad Mustaqim Junoh
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
External Magnetic Field ◽  
Differential Equations ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Stretching Sheet ◽  
Hartmann Number ◽  
Boundary Layer Separation ◽  
Radiation Parameter

The purpose of this research is to study the problem of mixed convection stagnation-point flow on a vertical stretching sheet with external magnetic field, with the effect of radiation is taken into account. The partial differential equations are reduced to ordinary differential equations using similarity transformation. The transformed boundary layer equations are then solved numerically via bvp4c in MATLAB software. The effects of different values of radiation parameter and Hartmann number on the skin friction coefficient and local Nusselt number, velocity and temperature profiles are presented and discussed. The effect of radiation parameter and Hartmann number are also considered for both assisting and opposing flows. Dual solutions are found to exist in the opposing flow only, while for assisting flow, unique solution exists. It is also found that the radiation parameter enhances the boundary layer separation, and the Hartmann number delays the boundary layer separation.

Mixed Magnetoconvection of Nanofluids in a Long Vertical Porous Channel

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Alessandra Borrelli ◽  
Giulia Giantesio ◽  
Maria Cristina Patria
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Volume Fraction ◽  
Reverse Flow ◽  
Boussinesq Approximation ◽  
Porous Channel ◽  
Nanoparticle Volume Fraction ◽  
Induced Magnetic Field ◽  
Two Phase ◽  
External Uniform Magnetic Field

Abstract This paper aimed to study the flow of a nanofluid in a long vertical porous channel when an external uniform magnetic field is impressed. The Buongiorno two-phase model of nanofluid is supposed to be slightly compressible in order to assume the Oberbeck–Boussinesq approximation. The velocity, the induced magnetic field, the temperature, and the nanoparticle volume fraction are analytically obtained. Detailed considerations are drawn for the occurrence of the reverse flow phenomenon. Moreover, a selected set of plots illustrating the influence of various parameters involved in the problem is presented and discussed.

scholarly journals Effect of magnetic field on nanofluid free convection in Conical Partially Annular Space

2020 ◽  
Vol 330 ◽  
pp. 01005
Author(s):  
Abderrahmane AISSA ◽  
Mohamed Amine MEDEBBER ◽  
Khaled Al-Farhany ◽  
Mohammed SAHNOUN ◽  
Ali Khaleel Kareem ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Boussinesq Approximation ◽  
Simulation Software ◽  
Comsol Multiphysics ◽  
Governing Equations ◽  
Element Analysis ◽  
Vertical Side ◽  
Side Walls

Natural convection of a magneto hydrodynamic nanofluid in a porous cavity in the presence of a magnetic field is investigated. The two vertical side walls are held isothermally at temperatures Th and Tc, while the horizontal walls of the outer cone are adiabatic. The governing equations obtained with the Boussinesq approximation are solved using Comsol Multiphysics finite element analysis and simulation software. Impact of Rayleigh number (Ra), Hartmann number (Ha) and nanofluid volume fraction (ϕ) are depicted. Results indicated that temperature gradient increases considerably with enhance of Ra and ϕ but it reduces with increases of Ha.

Effects of Second-Order Slip and Magnetic Field on Mixed Convection Stagnation-Point Flow of a Maxwellian Fluid: Multiple Solutions

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
M. M. Rahman
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Reverse Flow ◽  
Second Order ◽  
Dual Solutions ◽  
Stagnation Point Flow ◽  
Shrinking Sheet ◽  
Variable Surface

In this paper, we investigate the effects of second-order slip and magnetic field on the nonlinear mixed convection stagnation-point flow toward a vertical permeable stretching/shrinking sheet in an upper convected Maxwell (UCM) fluid with variable surface temperature. Numerical results are obtained using the bvp4c function from matlab for the reduced skin-friction coefficient, the rate of heat transfer, the velocity, and the temperature profiles. The results indicate that multiple (dual) solutions exist for a buoyancy opposing flow for certain values of the parameter space irrespective to the types of surfaces whether it is stretched or shrinked. It is found that an applied magnetic field compensates the suction velocity for the existence of the dual solutions. Depending on the parametric conditions; elastic parameter, magnetic field parameter, first- and second-order slip parameters significantly controls the flow and heat transfer characteristics. The illustrated streamlines show that for upper branch solutions, the effects of stretching and suction are direct and obvious as the flow near the surface is seen to suck through the permeable sheet and drag away from the origin of the sheet. However, aligned but reverse flow occurs for the case of lower branch solutions when the mixed convection effect is less significant.

scholarly journals Effects of Thermal Radiation, Heat Generation, and Induced Magnetic Field on Hydromagnetic Free Convection Flow of Couple Stress Fluid in an Isoflux-Isothermal Vertical Channel

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Hasan Nihal Zaidi ◽  
Mohammed Yousif ◽  
S. Nazia Nasreen
Keyword(s):  
Magnetic Field ◽  
Couple Stress ◽  
Channel Wall ◽  
Vertical Channel ◽  
Convection Flow ◽  
Induced Current ◽  
Induced Magnetic Field ◽  
Radiation Heat ◽  
Free Convection Flow ◽  
Radiation Heat Generation

The study scrutinizes the effects of thermal radiation, heat generation, and induced magnetic field on steady, fully developed hydromagnetic free convection flow of an incompressible viscous and electrically conducting couple stress fluid in a vertical channel. The channel walls are maintained at an isoflux-isothermal condition, such that the left channel wall is maintained at a constant heat flux. In contrast, the right channel wall is maintained at a constant temperature. The governing simultaneous equations are solved analytically utilizing the method of undetermined coefficient, and closed form solutions in dimensionless form have been acquired for the velocity field, the induced magnetic field, and the temperature field. The expression for the induced current density has been also obtained. A parametric study for the velocity, temperature, and induced magnetic field profiles, as well as for the skin-friction coefficient, Nusselt number, and induced current density, is conducted and discussed graphically.

scholarly journals Induced Magnetic Field in a Finite Fermion Density Maxwell QED2+1

1997 ◽  
Vol 12 (12) ◽  
pp. 877-886 ◽  
Author(s):  
Vadim Zeitlin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Gauge Field ◽  
The State ◽  
Landau Levels ◽  
Induced Magnetic Field ◽  
Field Mass ◽  
Chern Simons

We are studying finite fermion density states in Maxwell QED 2+1 with external magnetic field. It is shown that at any fermion density the energy of some magnetized states may be less than that of the state with the same density, but no magnetic field. Magnetized states are described by the effective Maxwell–Chern–Simons QED 2+1 Lagrangian with gauge field mass proportional to the number of filled Landau levels.

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