Effects of a vertical discontinuity in a porous medium on a plane convection plume at high Rayleigh numbers (Q1059513)

Standard methods exist for obtaining higher-order boundary-layer solutions at high Rayleigh numbers for convection flows in fluid- saturated porous media. The properties of the medium are usually considered uniform, however, and this is rarely the case in physical situations. We extend the theory to the case where the medium consists of two half-planes each with different permeabilities and diffusivities. A plane convection plume at the interface between the different media will be affected by this discontinuity, and we obtain results for the centreline velocity and concentration in terms of the ratios of permeabilities and diffusivities. Crossflow only occurs at second order, and many unexpected symmetries of the flow are found. These results should be of practical interest in tracer tests to identify heterogeneities in porous rocks.