Numerical investigation of the stability of mixed convection in a differentially heated vertical porous slab

摘要

The stability of mixed convection in a vertical porous slab whose vertical walls are rigid and maintained at constant but different temperatures is investigated in the presence of gravity. The Brinkman-extended Darcy model is used as the momentum equation. The disturbance stability equations are solved numerically using the Chebyshev collocation method. The neutral stability curves and the critical values of the Darcy–Rayleigh number, the corresponding wave number, and the wave speed are obtained for different values of the governing parameters. Contrary to the result observed in the case of pure natural convection, it is found that stationary instability disappears in the presence of a pressure gradient. The results for the Darcy case are delineated as a particular case from the present study and it is shown that the system is unconditionally stable.