The present study deals with an unsteady magnetohydrodynamic natural convective flow of a viscous, incompressible fluid past an exponentially accelerated porous plate surrounded by a porous medium with suction or injection. The novelty of the current research is to analyze the behavior of the flow due to mass transfer with first-order chemical reaction in the presence of a heat source in the energy equation. The

The present research work concentrates on viscous dissipation, Dufour, and heat source on an unsteady magnetohydrodynamics natural convective flow of a viscous, incompressible, and electrically conducting fluid past an exponentially accelerated infinite vertical plate in the existence of a strong magnetic field. The presence of the Hall current induces a secondary flow in the problem. The distinguishing features of viscous dissipation and heat flux produced due to gradient of concentration included in the model along with heat source as they are known to arise in thermal‐magnetic polymeric processing. The flow equations are discretized implicitly using the finite difference method and solved using MATLAB fsolve routine. Numerical values of the primary and secondary velocities, temperature, concentration, skin friction, Nusselt number, and Sherwood number are illustrated and presented via graphs and tables for various pertinent parametric values. The Dufour effect was observed to strengthen the velocity and temperature profile in the flow domain. In contrast, due to the impact of viscous dissipation, the local Nusselt number reduces. The study also reveals that the inclusion of the chemical reaction term augments the mass transfer rate and diminishes the heat transfer rate at the plate.

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The current research investigates the magnetohydrodynamic (MHD) slip flow of second-grade nanofluids past a permeable stretching sheet in a porous medium. The flow analysis is accomplished considering thermophoresis, Brownian diffusion, chemical reaction, and elastic deformation. The implementation of the Modified Buongiorno model (MBM) on second-grade nanofluid is the novel aspect of the study. The formulated coupled nonlinear equations are non-dimensionalized, applying suitable similarity transformation. Numerical resolution of the resulting equations is achieved via MATLAB solver bvp4c. In our problem, two different groups of nanofluids, $Cu-EO$ and $TiO_2-EO$, have been considered. The development of profiles of nanofluid velocity, temperature, concentration, entropy generation and Bejan number, with the flow parameters, is elaborated graphically. Tabulated values of skin friction, Nusselt number, and Sherwood number are illustrated. The principal outcomes of this study demonstrate a higher rate of heat transfer of $Cu-EO$ nanofluid than $TiO_2-EO$ nanofluid. The Nusselt number significantly decelerates, and the Sherwood number accelerates due to the combined influence of the Brownian diffusion and thermophoresis parameters. The second-grade parameter and nanoparticle volume fraction boost the skin friction magnitude. Furthermore, the entropy generation increases due to the Brinkman number and concentration diffusion parameter. The present research can be utilized to enhance the effectiveness of cooling systems in automobile engines, nuclear reactors, and heat exchangers. For the validation of our result, a comparative study is made with the previous authors and concludes in good agreement.

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