Mixed convection heat and mass transfer with thermal radiation in a non-Darcy porous medium

Similarity analysis is presented for simultaneous thermal radiation and mixed convection heat and mass transfer in thermal and solutal boundary layers over a semi-infinite vertical flat plate embedded in a fluid-saturated porous medium. The fluid is considered to be a gray, absorbing-emitting radiation but nonscattering and obeys Rosseland approximation for thermal radiation heat flux. It is observed that the radiation parameter R and temperature ratio C-T enhance the heat transfer coefficient in the aiding flow, and their effect is more profound in the Darcy medium rather than in the non-Darcy medium. Even though the effect of radiation is to enhance the heat transfer rate in both aiding and opposing flows, it is more significant in the aiding flow. Unlike in the aiding-flow case, both in opposing-flow and in opposing-buoyancy cases, the effect of radiation is more pronounced in the non-Darcy medium. The effect of R and C-T is to marginally increase the mass transfer coefficient. Even though radiation parameter does not have a direct impact oil the mass transfer coefficient, it is worth mentioning that the mass transfer coefficient increases as a function of the Lewis number, more in the presence of radiation than in its absence.