Radiative MHD flow over a vertical permeable surface with synergistic Soret and Dufour effects

Abstract

This work investigates the simultaneous influence of Soret (thermo-diffusion) and Dufour (diffusion-thermo) effects on magnetohydrodynamic (MHD) flow past a radiative elongated vertical plate embedded in a permeable medium, considering heat generation, magnetic fields, and chemical reactions. The governing nonlinear partial differential equations for momentum, energy, and concentration transport are transformed into a system of ordinary differential equations using similarity transformations and solved numerically via the MATLAB bvp4c solver, ensuring stability, convergence, and accuracy. Validation against previously published studies demonstrates excellent agreement, confirming the reliability of the present model. The results reveal pronounced parameter sensitivity of velocity, temperature, and concentration distributions. An increase in the magnetic parameter ($M:$ 0.5 → 1.5) reduces velocity by 12–15% and lowers the wall temperature gradient by ∼7.6% due to Lorentz force resistance, while radiation ($R:$1 → 3) suppresses velocity by 8–10% and decreases the thermal gradient by ∼6.5%, reflecting enhanced radiative losses. Higher Schmidt number ($\mathrm{Sc}$: 0 → 1.5) decreases velocity and wall concentration gradient by ∼8% and 10.1%, respectively, whereas the chemical reaction parameter ($\mathrm{Kc}$: 1 → 3) increases velocity by ∼7% and enhances the concentration gradient by ∼4.4%. The Dufour and Soret effects exhibit dual roles: while both reduce velocity (by ∼7–9% and ∼ 6–8%), they substantially amplify mass transfer, with wall concentration gradients increasing by 66.7% and 37.5%, respectively. These findings establish that magnetic, radiative, and diffusive mechanisms tend to suppress momentum, heat, and mass transport near the wall, whereas Soret and Dufour effects significantly intensify coupled transport processes. The study not only clarifies the competing influences of thermal, solutal, and electromagnetic mechanisms but also provides valuable guidance for optimizing thermal and mass transfer control in MHD-based engineering and porous media applications.