Gravity Modulation of Thermal Instability in a Viscoelastic Fluid Saturated Anisotropic Porous Medium

Abstract

The present paper deals with a thermal instability problem in a viscoelastic fluid saturating an anisotropic porous medium under gravity modulation. To find the gravity modulation effect, the gravity field is considered in two parts: a constant part and an externally imposed time-dependent periodic part. The time-dependent part of the gravity field, which can be realized by shaking the fluid, has been represented by a sinusoidal function. Using Hill's equation and the Floquet theory, the convective threshold has been obtained. It is found that gravity modulation can significantly affect the stability limits of the system. Further, we find that there is a competition between the synchronous and subharmonic modes of convection at the onset of instability. Effects of various parameters on the onset of instability have also been discussed.

Natural Convection in a Hydrodynamically and Thermally Anisotropic Non-Rectangular Porous Cavity: Effect of Internal Heat Generation/Absorption

“…On the other hand, a number of investigations on stability analyses relating to the onset of convection in porous media of finite thickness or finite lateral extent have also considered various anisotropic features. For references on all aforementioned aspects of anisotropic properties in free convective flows, one may refer to works reported in [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”