Magnetohydrodynamic second-grade nanofluid flow containing nanoparticles and gyrotactic microorganisms

The steady two-dimensional magnetohydrodynamic second-grade nanofluid flow containing nanoparticles and gyrotactic microorganisms is considered using passively controlled nanofluid model boundary conditions. For the biofluid, the thermal boundary layer convective boundary conditions have been handled. The study has been restricted to gyrotactic microorganisms where compensating torques generated by shear and gravity effects manifest in gyrotaxis which controls the orientation of upswimming microorganisms through rotary motions. Using the appropriate similarity transformation for the velocity, temperature, nanoparticle volume fraction and motile microorganism density, the governing partial differential conservation equations under prescribed boundary conditions are transformed to the ordinary differential equations which are solved analytically by the homotopy analysis method. Graphical solutions are presented to show the influences of all the parameters. Skin friction, wall heat transfer rate, nanoparticle mass transfer rate and microorganism transfer rate are evaluated in Table. Motile microorganism density function enhances with an increase in momentum slip. Bioconvection nanofluid is prepared by the cumulative involvement of buoyancy forces and magnetic field in the presence of gyrotactic microorganisms and copper nanoparticles which is relevant to advanced nanomechanical bioconvection energy conversion devices, bio-nano-coolant deployment systems, etc.