Bioconvective Casson fluid flow over a slender needle under magnetic dipole influence: Coupled thermal and chemical transport analysis

Precise control of non-Newtonian biofluids is essential in biomedical and thermal engineering applications, where heat and mass transfer must be carefully regulated. This study explores the steady two-dimensional bioconvective flow of a Casson fluid over a slender needle under a localized magnetic dipole, incorporating the effects of thermal radiation, Joule heating, and homogeneous chemical reactions. The governing nonlinear equations are transformed via similarity techniques and solved numerically using a Runge–Kutta method with a shooting scheme, with accuracy ensured through convergence and mesh-independence tests. Results reveal that magnetic interactions profoundly alter the flow, enhancing surface shear stress and increasing skin friction by up to 16 %, while reducing heat transfer due to magnetic damping and thermal energy accumulation in the boundary layer. These findings demonstrate the novelty of employing localized magnetic fields to actively manipulate bioconvective transport in Casson fluids, offering valuable insights for the design of magnetically guided biomedical devices and advanced thermal management systems.