The effect of perfectly conducting side walls on natural convection in porous media

An investigation of natural convection in a porous medium heated from below or above, and bounded by perfectly conducting side walls, shows that a motionless solution is impossible, except for a particular side wall temperature variation. Hence, convection occurs regardless of the value of Rayleigh number and regardless of whether the fluid is heated from below or from above. Numerical solutions for identical uniform temperatures imposed on both side walls (no temperature difference between the side walls) show that when heating from below, a subcritical flow results mainly near the side walls, which amplifies and extends over the entire domain under supercritical conditions.