The onset of Darcy‐Brinkman convection in a porous medium layer with vertical throughflow and variable gravity field effects

Heat Transfer ◽  
2020 ◽  
Vol 49 (5) ◽  
pp. 3161-3173 ◽  
Author(s):  
Dhananjay Yadav
Keyword(s):  
Porous Medium ◽  
Gravity Field ◽  
Field Effects ◽  
Medium Layer ◽  
Variable Gravity ◽  
Vertical Throughflow

scholarly journals VARIABLE GRAVITY FIELD AND THROUGHFLOW EFFECTS ON PENETRATIVE CONVECTION IN A POROUS LAYER

2013 ◽  
Vol 5 (3) ◽  
pp. 172-191 ◽  
Author(s):  
Gangadharaiah Y. H. ◽  
Suma S. P ◽  
Ananda K.
Keyword(s):  
Porous Medium ◽  
Gravity Field ◽  
Porous Layer ◽  
Perturbation Technique ◽  
Internal Heat ◽  
Wave Number ◽  
Penetrative Convection ◽  
Variable Gravity ◽  
Vertical Throughflow ◽  
The Stability

The effect of vertical throughflow and variable gravity field on the onset of penetrative convection simulated via internal heating in a porous medium is studied. Flow in the porous medium is governed by Forchheimer-extended Darcy equation. The boundaries are considered to be rigid, however permeable, and insulated to temperature perturbations. The eigen value problem is solved using a regular perturbation technique with wave number as a perturbation parameter. The variable gravity parameter, the direction of throughflow and the presence of volumetric internal heat source in a porous layer play a decisive role on the stability characteristics of the system. In addition, the influence of Prandtl number arising due to throughflow is also emphasized on the stability of the system. It is observed that both stabilizing and destabilizing factors can be enhanced due to the simultaneous presence of a volumetric source, gravity field and vertical throughflow so that a more precise control (suppress or augment) of thermal convective instability in a layer of porous medium is possible.

The Effect of Vertical Throughflow on Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid: A Revised Model

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
D. A. Nield ◽  
A. V. Kuznetsov
Keyword(s):  
Boundary Condition ◽  
Porous Medium ◽  
Porous Media ◽  
Thermal Instability ◽  
Volume Fraction ◽  
Critical Rayleigh Number ◽  
Nanoparticle Volume Fraction ◽  
Governing Equations ◽  
Medium Layer ◽  
Vertical Throughflow

The model developed in our previous paper (Nield and Kuznetsov, 2011, “The Effect of Vertical Throughflow on Thermal Instability in a Porous Medium Layer Saturated by a Nanofluid,” Transp. Porous Media, 87(3), pp. 765–775) is now revised to accommodate a more realistic boundary condition on the nanoparticle volume fraction. The new boundary condition postulates zero nanoparticle flux through the boundaries. We established that in the new model, oscillatory instability is impossible. We also established that the critical Rayleigh number depends on three dimensionless parameters, and we derived these three parameters from the governing equations. We also briefly investigated the major trends.

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