Impact of gyrotactic microorganisms on natural nanofluid bioconvection flow by a sphere immersed in porous media

A boundary layer treatment of nonsimilar models is performed to assay steady natural convection by gyrotactic microorganisms around an isothermal sphere placed in Darcy porous medium loaded by nanofluid. The current flow pattern involves the gyrotactic microorganisms alongside nanoparticles, and the sphere is related to concentration of nanoparticles and also motile microorganisms density. The benefits of suspended motile microorganisms in the fluid is to strengthen mass transfer, microscale mixing, and anticipated improved stability of the nanofluid. Newtonian nanofluid patterns embody the aspects of Brownian motion and thermophoresis. A convenient set of dimensionless factors are imposed, and nonsimilar equations governing the flow are deduced. After that, the derived partial differential equations (PDEs) are solved numerically using a Runge-Kutta-Fehlberg approach associated with shooting technique. A parametric investigation of the flow regime is done to interpret the impacts of the controlling parameters, such as Brownian motion factor, bioconvection Peclet number, bioconvection Lewis number, buoyancy ratio parameter, traditional Lewis number, thermophoresis factor, and bioconvection Rayleigh number. Relevant outcomes are displayed graphically. Mainly, increasing thermophoretic parameter enhances momentum (hydrodynamic) boundary layer thickness and nanoparticle boundary layer thickness, whereas it weakens thermal boundary layer thickness. The basic finding is the bioconvection factors are influenced by the heat, mass, and motile microorganism transport rates strongly.