Publication

Abstract : Bioconvection phenomena have gained significant attention in recent years due to their vital role in a wide range of industrial, biomedical, and environmental engineering applications. Motivated by their practical importance, the present study investigates the bioconvective Darcy–Forchheimer flow of an incompressible hydromagnetic Ree–Eyring non-Newtonian nanofluid past a vertically stretching porous sheet with chemical reactivity. The flow system is influenced by multiple physical mechanisms, including a uniform magnetic field, internal heat generation, radiative heat transfer (modeled using the Rosseland approximation), entropy generation, and the motion of gyrotactic microorganisms. Buongiorno’s nanofluid model is employed to incorporate the effects of Brownian motion and thermophoresis, while nonlinear mixed convection arises due to gradients in temperature, solutal concentration, and microorganism density. The model also accounts for cross-diffusion effects (Soret and Dufour), viscous dissipation, and the presence of activation energy to simulate temperature-sensitive chemical reactions. By applying boundary layer approximations, the governing partial differential equations are converted into a system of nonlinear ordinary differential equations using similarity transformations. These equations are numerically solved using MATLAB’s bvp4c solver. The effects of various key parameters on velocity, temperature, concentration, microorganism density, entropy generation, and associated transport characteristics such as skin friction coefficient, Nusselt number, Sherwood number, and motile microorganism number are illustrated through detailed graphical and tabular analysis. The results indicate that the axial velocity of the Ree–Eyring fluid increases with both the velocity ratio and material parameters, while magnetic effects tend to suppress it. Moreover, the microorganism density profile decreases with increasing values of the bioconvection Peclet number and Lewis number. The findings of this research provide useful insights for optimizing thermofluidic systems and improving energy and mass transport efficiency in nanofluid-based bioconvective applications.