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1

The onset of Soret driven ferrothermoconvective instability in the presence of darcy porous medium with anisotropy effect and MFD viscosity

Murugan D., Sekar R.

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 1

156--177

EN

The effect of magnetic 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.

2

Penetrative convection due to absorption of radiation in a magnetic nanofluid saturated porous layer

Mahajan Amit, Sharma Mahesh Kumar

Studia Geotechnica et Mechanica

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2019

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Vol. 41, nr 3

129--142

EN

The present study investigates the onset of penetrative convection induced by selective absorption of radiation in a magnetic nanofluid saturated porous medium. The influence of Brownian motion, thermophoresis, and magnetophoresis on magnetic nanofluid treatment is taken into consideration. The Darcy’s model is selected for the porous medium. We conduct a linear stability analysis to examine the onset of instability and evaluate the results for two different configurations, namely, when the layer is heated from below and when the layer is heated from above. The numerical investigations are carried out by applying the Chebyshev pseudospectral method. The effect of the porosity parameter E, parameter Y (represents the ratio of internal heating to boundary heating), Lewis number Le, concentration Rayleigh number Rn, Langevin parameter αL, width of nanofluid layer d, diffusivity ratio η, and modified diffusivity ratio NA is examined at the onset of convection. The results indicate that the convection commences easily with an increase in the value of Y, Le, and NA but opposite in the case with a decrease in the value of E, αL, η and d for both the two configurations. The parameter Rn advances the onset of convection when the layer is heated from below, while delays the onset of convection when the layer is heated from above.

3

Linear stability effect of densely distributed porous medium and Coriolis force on Soret driven ferrothermohaline convection

Sekar R., Murugan D.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 4

911--928

EN

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.

4

A study of natural convection in anisotropic porous rectangular channels using a thermal non-equilibrium model

Balagondar P. M., Pranesha Setty A.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 1

5-16

EN

A study of natural convection in a two dimensional rectangular channel filled with anisotropic porous media is considered, when the fluid and solid phases are not in local thermal equilibrium. Walls of the channel are non-uniformly heated to establish a linear temperature gradient and they are assumed to be impermeable and perfectly conducting. Darcy model with anisotropic permeability is used to describe the flow and a two field models are used for energy equation each representing fluid and solid phases separately. The critical Rayleigh number for the onset of convection using linear stability analysis is obtained numerically as a function of mechanical anisotropy parameters, interphase heat transfer coefficient and aspect ratio, and the same is plotted graphically, and discussed in detail.