Ferrothermoconvective instability of Soret-driven convection in a densely packed anisotropic porous medium

International Journal of Applied Mechanics and Engineering

2021

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The effect of magnetic field dependent (MFD) viscosity on Soret driven ferrothermohaline convection in a densely packed anisotropic porous medium has been studied. The Soret effect is focused on the system. A linear stability analysis is carried out using a normal mode technique and a perturbation method is applied. It is found that a stationary mode is favorable for the Darcy model. Vertical anisotropy tends to destabilize the system and the magnetization effect is found to stabilize the system. It is also found that the MFD viscosity delays the onset of convection. Numerical computations are made and illustrated graphically.

Section: Discussionsupporting

confidence: 85%

The Onset of Soret Driven Ferrothermoconvective Instability in the Presence of Darcy Porous Medium with Anisotropy Effect and MFD Viscosity

International Journal of Applied Mechanics and Engineering

2021

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“…When ▽ 2 q = 0 and Soret effect is absent, the critical Rayleigh number calculated in Hemalatha (2014). When δ = 0 and Soret effect is absent, one gets the thermal Rayleigh number is identical to Sekar et al (2016b). When k = ( k 1 , k 1 , k 2 ) and Soret effect is absent, the critical Rayleigh number derived by Sekar et al (2019).…”

Section: Resultsmentioning

confidence: 95%

“…Sekar and Vaidynathan, 1993;Sekar et al (1993a) investigated the ferroconvection in fluids saturating a rotating sparsely and densely packed porous medium. Sekar et al (2016aSekar et al ( , 2016b carried out the presence and absence of Coriolis force on ferrothermoconvective instability in Soret driven convection saturating a densely packed anisotropic porous medium. Sekar et al (2018Sekar et al ( , 2013 analyzed the presence and absence of Coriolis force on stability analysis of thermohaline convection in ferromagnetic fluid in densely packed porous medium with Soret effect.…”

Section: Introductionmentioning

confidence: 99%

A numerical technique and effect of magnetic field dependent (MFD) viscosity on thermal instability in a ferrofluid pores with Coriolis force for Darcy model

2021

WJE

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Purpose The effect of magnetic field dependent (MFD) viscosity on the onset of convection in a ferromagnetic fluid layer heated from below saturating rotating porous medium in the presence of vertical magnetic field is investigated theoretically by using Darcy model. The resulting eigen value problem is solved using the regular perturbation technique. Both stationary and oscillatory instabilities have been obtained. It is found that increase in MFD viscosity and increase in magnetic Rayleigh number is to delay the onset of ferroconvection, while the nonlinearity of fluid magnetization has no influence on the stability of the system. Design/methodology/approach The thermal perturbation method is employed for analytical solution. A theory of linear stability analysis and normal mode technique have been carried out to analyze the onset of convection for a fluid layer contained between two impermeable boundaries for which an exact solution is obtained. Findings The conditions for the system to stabilize both by stationary and oscillatory modes are studied. Even for the oscillatory system of particular frequency dictated by physical conditions, the critical Rayleigh numbers for oscillatory mode of the system were found to be greater than for the stationary mode. The system gets destabilized for various physical parameters only through stationary mode. Hence, the analysis is restricted to the stationary mode. To the Coriolis force, the Taylor number Ta is calculated to discuss the results. It is found that the system stabilizes through stationary mode for values of and for oscillatory instability is favored for Ta > 104. Therefore the Taylor number Ta leads to stability of the system. For larger rotation, magnetization leads to destabilization of the system. The MFD viscosity is found to stabilize the system. Originality/value This research paper is new and original.

“…Also, with and without magnetic field dependent (MFD) viscosity on Soret driven ferrothermohaline convection in an anisotropic porous medium was studied by Sekar and Raju [22][23].The effect of temperature dependent viscosity and Coriolis force on Soret driven ferrothermohaline convection in a porous medium and anisotropy effect was studied by Sekar et al [24][25]. Most recently, the presence and absence of Coriolis force on Soret driven ferrothermohaline convection saturating a densely packed anisotropic porous medium was studied by Sekar et al [26][27].…”

Section: Introductionmentioning

confidence: 99%

Linear Stability Effect of Densely Distributed Porous Medium and Coriolis Force on Soret Driven Ferrothermohaline Convection

International Journal of Applied Mechanics and Engineering

2018

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The effect of Coriolis force on the Soret driven ferrothermohaline convection in a densely packed porous medium has been studied. A linear stability analysis is carried out using normal mode technique. It is found that stationary convection is favorable for the Darcy model, therefore oscillatory instability is studied. A small thermal perturbation is applied to the basic state and linear stability analysis is used for which the normal mode technique is applied. It is found that the presence of a porous medium favours the onset of convection. The porous medium is assumed to be variable and the effect of the permeable parameter is to destabilize the system. The present work has been carried out both for oscillatory as well as stationary instabilities. The results are depicted graphically.