Abstract
The current study presents the dynamics of entropy generation in magnetohydrodynamic Cross nanofluid containing gyrotactic microorganisms. The system of nonlinear coupled differential equations is acquired through boundary layer approximation and appropriate similarity transformations. The system of equations is solved using the Optimal Homotopy Analysis Method (OHAM). The impressions of several emergent parameters are obtained and presented graphically. Contour plots are conferred for entropy generation and the Bejan number to explore the dynamism of flow in detail. Numerically calculated values of heat flux, mass flux, and fluxes for the concentrations of nanoparticles and motile microorganisms are exhibited in tabular forms. It is remarkable to note that the concentration of nanoparticles can be enhanced by controlling the Brownian motion parameter whereas the process of entropy generation can be controlled through temperature difference parameter.