MAXIMUM DENSITY EFFECTS ON VORTEX INSTABILITY OF HORIZONTAL AND INCLUDED BUOYANCY-INDUCED FLOWS IN POROUS MEDIA.

A linear stability theory is used to analyze the vortex instability of buoyancy-induced boundary layer flows adjacent to horizontal and inclined surfaces in porous media, such as coarse sands, saturated with cold water, wherein a density extremum may arise. The neutral stability equation is derived to include the effect of pressure and salinity in the absence of saline diffusion up to a maximum of 1000 bars and 40 parts per thousands. Numerical results indicate that as the density extreum parameter expressing the relationship among the imposed temperature and the extremum temperature increases, the heat transfer rate increases and the flow is more susceptible to the vortex instability; as the angle of inclination from the horizontal increases, the heat transfer rate increases, whereas the susceptibility of the flow to the vortex instability decreases.