Nonlinear Radiation-induced Magneto-bioconvective Transport in a Casson Nanofluid with Double Stratification and Velocity Slip Over a Stretching Surface
Liberty Ebiwareme
*
Department of Mathematics, Rivers State University, Port Harcourt, Nigeria.
Kubugha Bunonyo Wilcox
Department of Mathematics and Statistics, Federal University, Otuoke, Nigeria.
Fun-Akpo Kormane Pere
Department of Mathematics, Rivers State University, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
The steady two-dimensional magnetohydrodynamic boundary-layer flow of a non-Newtonian Casson nanofluid past a stretching surface, in the presence of velocity slip, thermal radiation, and bioconvection effects, is investigated in this study. The mathematical model incorporates the influences of Brownian motion and thermophoresis within the Buongiorno nanofluid framework, along with the dynamics of gyrotactic microorganisms. The governing nonlinear partial differential equations for momentum, energy, nanoparticle concentration, and microorganism density are formulated and transformed into a system of coupled ordinary differential equations using appropriate similarity transformations. The transformed system is solved numerically using the Adomian Decomposition Method. The effects of key physical parameters, including the Casson parameter, magnetic field strength, slip parameter, thermal radiation parameter, Brownian motion parameter, thermophoresis parameter, and bioconvection Lewis number, on the velocity, temperature, concentration, and microorganism density profiles are analysed in detail. The results reveal that increasing the magnetic parameter significantly suppresses the fluid velocity due to the Lorentz force, while enhancing thermal and concentration boundary-layer thicknesses. The presence of velocity slip is found to reduce surface shear stress, whereas thermal radiation intensifies the heat transfer rate within the boundary layer. Furthermore, the parameters of Brownian motion and thermophoresis play a crucial role in augmenting nanoparticle distribution, while bioconvection effects significantly influence microorganism density profiles. Engineering quantities of practical interest, such as the skin friction coefficient, local Nusselt number, Sherwood number, and motile microorganism density number, are computed and discussed. The present study provides insight into the relationship between magnetic fields, non-Newtonian behaviour, nanoparticle transport, and bioconvection, with potential applications in biomedical engineering, microfluidic devices, and advanced cooling technologies.
Keywords: Bioconvection, nanofluid, double stratification, Casson, thermal radiation