Taguchi optimized bioconvection rate in a Williamson–Buongiorno nanofluid flow through a rotating porous channel with Active–Passive control of nanoparticles flux

Purpose Nanofluids flow containing microorganisms are widely used in targeted drug delivery systems and biomedical devices. Based on these recent applications, the current study aims to explore the unsteady bioconvective flow driven by gyrotactic microorganisms of a Williamson–Buongiorno nanofluid through a rotating porous channel. Special attention is provided to the effects of thermal radiation, Soret effect, Dufour effect, chemical reaction and active–passive control of nanoparticles flux strategies. Design/methodology/approach The governing nonlinear partial differential equations are properly non-dimensionalized and then tackled numerically using an implicit finite-difference scheme of the Crank-Nicolson method. Alongside, Taguchi–analysis of variance (ANOVA) optimization is implemented to quantify the relative dominance of the governing parameters to the rate of bioconvection. Findings The passive control of nanoparticles flux showcases more significant impact over all the profiles in comparison to active control. Thermal radiation is observed to increase the heat transfer rate within the system, whereas the presence of chemical reaction affects the nanoparticles distribution and changes the bioconvective flow pattern. Taguchi–ANOVA confirms the dominance of the chemical reaction parameter followed by bioconvection Peclet number, over the bioconvection rate for both actively and passively controlled nanoparticles flux. Originality/value Bioconvective flow of Williamson–Buongiorno nanofluid with active–passive control of nanoparticles flux in a porous channel is the uniqueness of this study. In addition, this research demonstrates an advanced blend of numerical and optimization approach towards nanofluid dynamics.