TITLE:
Stability of Geothermal Convection in Anisotropic River Beds
AUTHORS:
Gérard Degan, Julien Yovogan, Latif Fagbémi, Zineddine Allou
KEYWORDS:
River Beds, Critical Rayleigh Numbers, Isotropic, Anisotropic
JOURNAL NAME:
Engineering,
Vol.11 No.7,
July
10,
2019
ABSTRACT: The onset of thermal convection, due to heating from
below in a system consisting of a fluid layer overlying a porous layer with
anisotropic permeability and thermal diffusivity, is investigated analytically.
The porous medium is both anisotropic in permeability whose principal axes are
oriented in a direction that is oblique to the gravity vector and in thermal conductivity
with principal directions coincident with the coordinate axes. The Beavers-Joseph
condition is applied at the interface between the two layers. Based on parallel
flow approximation theory, a linear stability analysis is conducted to study
the geothermal river beds system and documented the effects of the physical
parameters describing the problem. The critical Rayleigh numbers for both the
fluid and porous layers corresponding, to the onset of convection arising from
sudden heating and cooling at the boundaries are also predicted. The results obtained
are in agreement with those found in the past for particular isotropic and
anisotropic cases and for limiting cases concerning pure porous media and for
pure fluid layer. It has demonstrated that the effects of anisotropic
parameters are highly significant.