Unsteady MHD flow of Casson fluid in porous media with Soret and Dufour effects for biomedical applications

Abstract The unsteady magnetohydrodynamic (MHD) flow of a Casson fluid through a porous medium has significant applications in biomedical engineering, particularly in modelling blood flow through tissues and small blood vessels. It also contributes to understanding heat and mass transfer phenomena, such as oxygen transport, drug delivery, and thermal regulation, in the presence of Soret and Dufour effects. Motivated by these applications, the present study investigates the unsteady mixed convection MHD flow of a non-Newtonian Casson fluid under the influence of Soret and Dufour effects. The fluid flow past an exponentially accelerating vertical porous plate embedded in a porous medium is analyzed under ramped wall temperature and concentration conditions. Furthermore, the model incorporates the effects of chemical reaction, thermal radiation, Joule heating, and viscous dissipation. The governing coupled, nonlinear, and dimensionless differential equations are solved numerically using the finite difference method. The computational results are presented graphically to illustrate the effects of the governing parameters on the velocity, temperature, and concentration fields, while the skin-friction coefficient, Nusselt number, and Sherwood number are reported in tabular form. The results reveal that viscous dissipation, heat generation, thermal radiation, and the Dufour effect enhance both the velocity and temperature distributions of the Casson fluid. Likewise, increasing porosity and buoyancy parameters accelerates the fluid motion, whereas the Casson parameter and magnetic field strength suppress the flow velocity. Moreover, the Soret effect increases both the velocity and concentration profiles, while chemical reactions reduce the concentration field. It is also observed that higher values of viscous dissipation, Dufour effect, and heat generation lead to a decrease in the Nusselt number and skin-friction coefficient.