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.

POROUS PENETRATIVE CONVECTION WITH A SALT FIELD AND INTERNAL HEAT SOURCE

1992 ◽  
Vol 02 (04) ◽  
pp. 407-421
Author(s):  
LORNA RICHARDSON
Keyword(s):  
Porous Medium ◽  
Temperature Gradient ◽  
Heat Source ◽  
Nonlinear Stability ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Penetrative Convection ◽  
Weighted Energy ◽  
The Stability ◽  
Unconditional Nonlinear Stability

We investigate the stability of convection in a porous medium containing a heat source in which a destabilizing salt field and stabilizing temperature gradient are present. Both conditional and unconditional nonlinear stability thresholds are calculated and we note that RaE(conditional)>RaE(unconditional). The unconditional nonlinear analysis requires the use of a “weighted” energy.

Variable Viscosity Effects on Penetrative Convection in a Fluid Layer

2017 ◽  
Vol 13 (3) ◽  
pp. 51-65
Author(s):  
Gangadharaiah Y H
Keyword(s):  
Surface Deformation ◽  
Variable Viscosity ◽  
Fluid Layer ◽  
Perturbation Technique ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Decisive Role ◽  
Wave Number ◽  
Regular Perturbation ◽  
Penetrative Convection

The effect of variable viscosity on the onset of penetrative convection simulated via internal heating in a fluid layer. The upper surface of a fluid layer is assumed to be deformably free and dependence of viscosity is assumed to be exponential. The resulting eigen value problem is solved using a regular perturbation technique with wave number a as a perturbation parameter. The viscosity parameter, surface deformation and the presence of internal heat source play a decisive role on the stability characteristics of the system.

scholarly journals Two-Dimensional Convection Induced by Gravity and Centrifugal Forces in a Rotating Porous Layer Far Away from the Axis of Rotation

1998 ◽  
Vol 4 (2) ◽  
pp. 73-90 ◽  
Author(s):  
Peter Vadasz ◽  
Saneshan Govender
Keyword(s):  
Rayleigh Number ◽  
Porous Layer ◽  
Temperature Fields ◽  
Wave Number ◽  
Marginal Stability ◽  
Two Dimensional ◽  
Wide Range ◽  
Gravity Driven ◽  
Gravity Driven Flow ◽  
The Stability

The stability and onset of two-dimensional convection in a rotating fluid saturated porous layer subject to gravity and centrifugal body forces is investigated analytically. The problem corresponding to a layer placed far away from the centre of rotation was identified as a distinct case and therefore justifying special attention. The stability of a basic gravity driven convection is analysed. The marginal stability criterion is established in terms of a critical centrifugal Rayleigh number and a critical wave number for different values of the gravity related Rayleigh number. For any given value of the gravity related Rayleigh number there is a transitional value of the wave number, beyond which the basic gravity driven flow is stable. The results provide the stability map for a wide range of values of the gravity related Rayleigh number, as well as the corresponding flow and temperature fields.

Convection in a porous medium with variable internal heat source and variable gravity

2017 ◽  
Vol 111 ◽  
pp. 651-656 ◽  
Author(s):  
U.S. Mahabaleshwar ◽  
D. Basavaraja ◽  
Shaowei Wang ◽  
Giulio Lorenzini ◽  
Enrico Lorenzini
Keyword(s):  
Porous Medium ◽  
Heat Source ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Variable Gravity

scholarly journals Effect of Vadasz Number on Magnetoconvection in a Darcy Porous Layer with Concentration Based Internal Heating

2019 ◽  
pp. 1-13
Author(s):  
C. Israel-Cookey ◽  
L. Ebiwareme ◽  
E. Amos
Keyword(s):  
Magnetic Field ◽  
Rayleigh Number ◽  
Porous Layer ◽  
Internal Heat ◽  
Lewis Number ◽  
Mode Analysis ◽  
Internal Heating ◽  
Vadasz Number ◽  
The Stability ◽  
Solutal Rayleigh Number

In this research article, the effect of Vadasz number on magnetoconvection in a Darcy Porous Layer with concentration based internal heating is studied. The flow is governed by the Oberbeck-Boussineq model for Newtonian fluid. The stability analysis method based on the perturbation of infinitesimal amplitude is carried out using the normal mode analysis. The onset criterion for both the stationary and oscillatory convection on the stability of system is obtained. The analysis examines the effects of pertinent parameters on the stability of the system: magnetic field parameter, solutal Rayleigh number, Lewis number and Vadasz number. The result show that, internal heat parameter,  and Lewis number, , hastens the onset of instability in the system, whereas magnetic field, , Vadasz number,  and solutal Rayleigh number,  delay the onset of instability.

Effect of a Variable Gravity Field on Convection in an Anisotropic Porous Medium With Internal Heat Source and Inclined Temperature Gradient

2001 ◽  
Vol 124 (1) ◽  
pp. 144-150 ◽  
Author(s):  
Sherin M. Alex ◽  
Prabhamani R. Patil
Keyword(s):  
Temperature Gradient ◽  
Heat Source ◽  
Gravity Field ◽  
Convective Instability ◽  
Opposite Effect ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Anisotropic Porous Medium ◽  
Variable Gravity ◽  
Inclined Temperature Gradient

The convective instability of a horizontal fluid-saturated anisotropic porous layer, with internal heat source and inclined temperature gradient, subject to a gravity field varying with distance in the layer, is investigated. A linear stability analysis is performed and the resulting eigenvalue problem solved using a Galerkin technique. In the absence of an inclined temperature gradient, an increase in the variable gravity parameter above −1 destabilizes the system. In its presence interesting developments occur. An increase in the heat generation destabilizes the system when the variable gravity parameter is nonnegative. When it is negative the opposite effect is seen.

Effects of Variable Gravity Field on the Onset of Ferroconvection in an Anisotropic Porous Layer

2021 ◽  
pp. 851-861
Author(s):  
S. Kiran ◽  
Y. H. Gangadharaiah ◽  
H. Nagarathnamma ◽  
R. Padmavathi
Keyword(s):  
Gravity Field ◽  
Porous Layer ◽  
Variable Gravity
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