Suction/Injection Analysis of MHD Bioconvective Casson Fluid Flow Over a Darcy–Forchheimer Porous Stretching Sheet With Thermal Radiation, Double Diffusion, and Ohmic–Viscous Dissipation Effects

This study examines the magnetohydrodynamic (MHD) flow of a Casson nanofluid over a permeable stretching sheet incorporating the combined influence of suction/injection, ohmic and viscous dissipation, thermal radiation, and Arrhenius activation energy. The Cattaneo‐Christov double diffusion model is employed to capture non‐Fourier heat and mass flux behavior. The presence of gyrotactic microorganisms introduces bioconvection effects, enhancing the practical relevance of the model to biological and industrial systems including coolant design, bioreactors, drug delivery, biomedical engineering, thermal management, and environmental remediation. The governing nonlinear partial differential equations are transformed to a system of coupled ordinary differential equations via appropriate similarity transformations. The resulting boundary value problem is solved numerically using the MATLAB built‐in solver bvp4c with a relative tolerance of and Runge‐Kutta Fehlberg(RKF) method using Maple software that uses to ‐order RKF numerical quadrature as a default method. Results are validated against two previously published studies. The influence of key parameters–including the magnetic parameter, Eckert number, Prandtl number, Schmidt number, Lewis number, Péclet number, and Arrhenius activation energy on the velocity, temperature, concentration, and microorganism density profiles is examined graphically and tabularly. It is found that increasing the magnetic parameter suppresses the velocity profile while enhancing the thermal boundary layer thickness due to Ohmic heating. The Nusselt number decreases with rising Eckert number, whereas the presence of motile microorganisms significantly enhances the heat transfer rate. Increasing activation energy elevates the concentration profile, while the Cattaneo‐Christov model yields a thinner thermal boundary layer compared to the classical Fourier model. The motile microorganism density decreases with rising Péclet number. The skin friction coefficient, Nusselt number, and Sherwood number are computed and validated against previously published results, showing excellent agreement within 0.5. The magnetic parameter is found to reduce the skin friction coefficient by approximately 12 and enhance the local Nusselt number by 8 through Ohmic heating at selected parameter values.