Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
Three-Dimensional instability analysis in a porous medium with inclined temperature gradient and horizontal and vertical throughflow
Submission Author:
Mateus Schuabb , RJ
Co-Authors:
Mateus Schuabb, Leonardo Santos de Brito Alves
Presenter: Mateus Schuabb
doi://10.26678/ABCM.ENCIT2018.CIT18-0386
Abstract
In this article, the three-dimensional convective and absolute instabilities applying the approach of linear instability analysis in an extended horizontal layer of a saturated porous medium with inclined temperature gradient and horizontal and vertical throughflow are analyzed for a variety of values of horizontal Rayleigh number, Rh, and the Péclet number, Qv. The control parameter is the vertical Rayleigh number, Rv, which represent the temperature difference between the contours. The computations are performed by using the shooting method for both convective and absolute analysis, where it can guarantee a minimum and a saddle point, respectively. The convective results are compared with the results found in the literature. Due the difficulty in obtaining the critical values of the onset to absolute instability, mainly in three-dimensional analysis, there is not a complete mapping about the absolute instability. The absolute results in the literature are found indirectly through the convective analysis calculating the group velocities. All convective results compare well with the results found in the literature, where there is a stabilization effect with the increase of both Rh and Qv. The absolute results are in agreement with the few results found in literature. Although, there are competition between the transverse and longitudinal modes to be the critical, the control parameter increases when both Rh and Qv are function. When the transverse modes are the critical, the disturbance is oscillatory, when it is longitudinal, it is non-oscillatory.
Keywords
Darcy flow, Inclined temperature gradient, Stability of transverse modes, Absolute and convective instability
