Analysis of Gyrotactic Microorganism-Induced Bioconvective Transport and Flow Dynamics in Micropolar Nanofluids over an Exponentially Expanding Surface with Thermal and Solutal Effects

This study aims to investigate bioconvective flow in non-Newtonian micropolar nanofluids over a porous, stretchable surface, incorporating bioconvection to regulate solid nanoparticles. The analysis considers the effects of Brownian motion and thermophoresis, with the Buongiorno model, applied to the constitutive equations. Gyrotactic microorganisms are included to account for bioconvective effects. The momentum equation incorporates magnetic forces and permeability, while the energy equation accounts for viscous dissipation and thermal radiation. Mass concentration is modeled using Activation energy and a binary chemical reaction, incorporating buoyancy effects into the thermal and concentration equations. The governing equations, formulated through boundary layer approximations, are converted into ordinary differential equations and solved using the Runge-Kutta method in MATLAB. For various parameter values, the study examines velocity, temperature, mass concentration, and motile microorganism density. Computationally evaluated skin friction, heat transfer, mass transfer, and density rates are also conducted. This research provides a foundational framework for scientists and engineers to understand better and control fluid flow while optimizing system performance. The findings have significant applications in biosciences, geosciences, and environmental sciences, where nanofluids with gyrotactic microorganisms are extensively used.