Internally heated penetrative Bénard-Marangoni ferroconvection: Effect of MFD viscosity

2021 ◽  
Author(s):  
R. Suprabha ◽  
C. R. Mahesha ◽  
C. E. Nanjundappa
Keyword(s):  
Mfd Viscosity

Brinkman ferromagnetic convection in a porous layer: Effect of MFD viscosity and magnetic boundaries

2013 ◽  
Vol 27 (12) ◽  
pp. 3875-3884 ◽  
Author(s):  
I. S. Shivakumara ◽  
Jinho Lee ◽  
C. E. Nanjundappa ◽  
M. Ravisha ◽  
D. H. Lee
Keyword(s):  
Porous Layer ◽  
Layer Effect ◽  
Ferromagnetic Convection ◽  
Mfd Viscosity

A nonlinear stability analysis in a double-diffusive magnetized ferrofluid with magnetic-field-dependent viscosity saturating a porous medium

2009 ◽  
Vol 87 (6) ◽  
pp. 659-673 ◽  
Author(s):  
Sunil ◽  
Amit Mahajan
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Nonlinear Stability ◽  
Stability Result ◽  
Darcy Number ◽  
Linear Instability ◽  
Nonlinear Stability Analysis ◽  
Field Dependent ◽  
Magnetized Ferrofluid ◽  
Mfd Viscosity

A rigorous nonlinear stability result is derived by introducing a suitable generalized energy functional for a magnetized ferrofluid layer heated and soluted from below with magnetic-field-dependent (MFD) viscosity saturating a porous medium, in the stress-free boundary case. The mathematical emphasis is on how to control the nonlinear terms caused by the magnetic-body and inertia forces. For ferrofluids, we find that there is possibility of existence of subcritical instabilities, however, it is noted that, in case of a non-ferrofluid, the global nonlinear stability Rayleigh number is exactly the same as that for linear instability. For lower values of magnetic parameters, this coincidence is immediately lost. The effect of the magnetic parameter, M3; solute gradient, Sf; Darcy number, Da; and MFD viscosity parameter, δ; on the subcritical instability region has also been analyzed.

scholarly journals The Effect of Magnetic Field Dependent Viscosity on Ferromagnetic Convection in a Rotating Sparsely Distributed Porous Medium - Revisited

2020 ◽  
Vol 25 (1) ◽  
pp. 142-158
Author(s):  
J. Prakash ◽  
P. Kumar ◽  
S. Manan ◽  
K.R. Sharma
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Critical Rayleigh Number ◽  
Wave Number ◽  
Stationary Mode ◽  
Free Boundaries ◽  
Field Dependent ◽  
Mfd Viscosity ◽  
Magnetic Field Dependent Viscosity ◽  
Dependent Viscosity

AbstractThe effect of magnetic field dependent (MFD) viscosity on the thermal convection in a ferrofluid layer saturating a sparsely distributed porous medium has been investigated by using the Darcy-Brinkman model in the simultaneous presence of a uniform vertical magnetic field and a uniform vertical rotation. A correction is applied to the study of Vaidyanathan et al. [11] which is very important in order to predict the correct behavior of MFD viscosity. A linear stability analysis has been carried out for stationary modes and oscillatory modes separately. The critical wave number and critical Rayleigh number for the onset of instability, for the case of free boundaries, are determined numerically for sufficiently large values of the magnetic parameter M1. Numerical results are obtained and are illustrated graphically. It is shown that magnetic field dependent viscosity has a destabilizing effect on the system for the case of stationary mode and a stabilizing effect for the case of oscillatory mode, whereas magnetization has a destabilizing effect.

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