Hydromagnetic Double-Diffusive Laminar Natural Convection in a Radiatively Participating Fluid

ABSTRACT

Two-dimensional hydromagnetic double-diffusive convection of a radiatively participating fluid confined in a rectangular enclosure is studied numerically for fixed Prandtl, Rayleigh, and Lewis numbers, Pr = 13.6, Ra = 10⁵, Le = 2. Uniform temperatures and concentrations are imposed along the vertical walls, while the horizontal walls are assumed to be adiabatic and impermeable. The damping and stabilization effects of an external horizontal magnetic field are studied for three different optical thicknesses of the semitransparent fluid as well as for an opaque medium. For moderate optical thickness, a steady compositionally dominated flow is observed for all values of Hartmann number considered, and the magnetic damping is remarkably lower than in the opaque medium, for which the flow is always thermally dominated. For optically thin and optically thick media, the thermally dominated flow is stabilized and becomes compositionally dominated as soon as the Hartmann number is increased.