Analysis of assisting and opposing mixed convection heat and mass transfer over inclined vertical plates in a porous medium

This study investigates the combined heat and mass transfer in mixed convection flow along vertical and inclined flat plates embedded in a porous medium. A mathematical problem is articulated based on the governing conservation laws and the prescribed coordinate system. The resultant system of collective nonlinear partial differential equations is reduced to a set of ordinary differential equations using a stream function formulation. The boundary value problem is solved numerically using a fourth-order Runge–Kutta method with appropriate iterative procedures to ensure convergence. The analysis emphasizes the influence of significant dimensionless parameters, together with the modified mixed convection parameter for heat and mass transfer [Formula: see text] and [Formula: see text], the Prandtl number [Formula: see text], the Schmidt number [Formula: see text], and the porous medium parameter [Formula: see text]. Numerical outcomes are accessible for velocity, temperature, and concentration distributions for assisting and opposed flow situations. Furthermore, the effects on engineering quantities such as skin friction, Nusselt number, and Sherwood number are examined in detail. The outcomes reveal that increasing [Formula: see text] and [Formula: see text] parameters significantly enhances skin friction and heat transfer rate in opposing flow, while offering additional resistance in assisting flow. The porous medium parameter is found to strongly regulate boundary layer thickness and flow resistance. These findings provide useful physical insights into mixed convection heat transfer in porous structures, with relevance to geophysical, environmental, and industrial applications.