Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Absolute Instability of mixed convection in a heated horizontal porous channel
Submission Author:
Nelson Rodrigues Braga junior , RJ , Brazil
Co-Authors:
Pedro Vayssiere Brandão, Leandro Alcoforado Sphaier, Leonardo Santos de Brito Alves, Nelson Rodrigues Braga junior
Presenter: Nelson Rodrigues Braga junior
doi://10.26678/ABCM.COBEM2017.COB17-2458
Abstract
The present paper employs a linear stability analysis with the purpose to investigate the transition from a convective to an absolute instability in a Darcy-Benard problem. The problem studied is a horizontal throughflow in a porous layer heated from below by an isoflux and internally by a heat source, and with a third kind boundary condition for the temperature at the top. A modal analysis is performed leading to an eigenvalue problem, which allow one to determine critical values for the Rayleigh number as a function of the Peclet number, the wavenumber, the time frequency and the internal heat source. The zero group velocity condition is applied in order to obtain the transition to the absolute instability. The problem is solved using the Generalized Integral Transform Technique (GITT).
Keywords
Mixed Convection, absolute stability, porous channel
