Effect of Variable Gravity Field on Thermal Instability in a Porous Medium with Inclined Temperature Gradient and Vertical Throughflow

2002 ◽  
Vol 5 (2) ◽  
pp. 11 ◽  
Author(s):  
Sherin M. Alex ◽  
Prabhamani R. Patil
Keyword(s):  
Porous Medium ◽  
Temperature Gradient ◽  
Gravity Field ◽  
Thermal Instability ◽  
Variable Gravity ◽  
Vertical Throughflow ◽  
Inclined Temperature Gradient

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.

Three-dimensional absolute and convective instabilities at the onset of convection in a porous medium with inclined temperature gradient and vertical throughflow

2009 ◽  
Vol 641 ◽  
pp. 475-487 ◽  
Author(s):  
LEONID BREVDO
Keyword(s):  
Porous Medium ◽  
Rayleigh Number ◽  
Temperature Gradient ◽  
Three Dimensional ◽  
Onset Of Convection ◽  
Convective Instabilities ◽  
Homogeneous Porous Medium ◽  
Vertical Throughflow ◽  
Speed Of Propagation ◽  
Inclined Temperature Gradient

By using the mathematical formalism of absolute and convective instabilities, we study in this work the nature of unstable three-dimensional localized disturbances at the onset of convection in a flow in a saturated homogeneous porous medium with inclined temperature gradient and vertical throughflow. It is shown that for marginally supercritical values of the vertical Rayleigh numberRvthe destabilization has the character of absolute instability in all the cases in which the horizontal Rayleigh numberRhis zero or the Péclet numberQvis zero. In all the cases in whichRhandQvare both different from zero, at the onset of convection the instability is convective. In the latter cases, the growing emerging disturbance has locally the structure of a non-oscillatory longitudinal roll, and its group velocity points in the direction opposite the direction of the applied horizontal temperature gradient, i.e. parallel to the axis of the roll. The speed of propagation of the unstable wavepacket increases withQvand generally increases withRh.

scholarly journals Thermal Instability of a Couple-Stress Ferromagnetic Fluid in the Presence of Variable Gravity Field and Horizontal Magnetic Field with Hall Currents Saturating in a Porous Medium

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Sudhir Kumar Pundir ◽  
◽  
Pulkit Kumar Nadian ◽  
Rimple Pundir ◽  
◽  
...  
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Gravity Field ◽  
Couple Stress ◽  
Thermal Instability ◽  
Horizontal Magnetic Field ◽  
Variable Gravity ◽  
Ferromagnetic Fluid

https://jusst.org/thermal-instability-of-a-couple-stress-ferromagnetic-fluid-in-the-presence-of-variable-gravity-field-and-horizontal-magnetic-field-with-hall-currents-saturating-in-a-porous-medium/

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