This paper presents the nonsimilarity solutions for mixed convection heat and mass transfer along a semi-infinite vertical plate embedded in a doubly stratified fluid saturated porous medium in the presence of Soret and Dufour effects. The flow in the porous medium is described by employing the Darcy-Forchheimer based model. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless forms and then solved numerically. The influence of pertinent parameters on dimensionless velocity, temperature, concentration, heat, and mass transfer in terms of the local Nusselt and Sherwood numbers is discussed and presented graphically. 1. Introduction The study of mixed convective transport in a doubly stratified (thermal and/or solutal stratification) fluid saturated porous medium has been a topic of continuing interest in the past decades owing to its importance in many industrial and engineering applications. These applications include heat rejection into the environment such as lakes, rivers, and seas; thermal energy storage systems such as solar ponds; and heat transfer from thermal sources such as the condensers of power plants. Numerous studies on mixed convection heat and mass transfer have been reported in the past several decades using both Darcian and non-Darcian models for the porous medium. Comprehensive reviews of convective heat transfer in porous medium can be found in the books by Nield and Bejan [1], Pop and Ingham [2], and Bejan [3]. Non-Darcian models are the extensions of the classical Darcy formulation to incorporate inertial drag effects, vorticity diffusion, and combinations of these effects. Different models such as Brinkman-extended Darcy, Forchheimer-extended Darcy, and the generalized flow models were proposed in the literature to analyze the non-Darcian flow in porous media. The Darcy-Forchheimer model is an extension of classical Darcian formulation obtained by adding a velocity squared term in the momentum equation to account for the inertial effects. Several authors have reported the study of mixed convection heat and mass transfer in porous medium for which the Forchheimer-extended Darcy model is employed. Stratification of fluid is a deposition/formation of layers and occurs due to temperature variations, concentration differences, or the presence of different fluids. It is important to examine the temperature stratification and concentration differences of hydrogen and oxygen in lakes and ponds as they may directly affect the growth rate of all cultured species. Also, the analysis
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