Modelling forced convection and magneto-elastic interactions in a downward conduit using ferrofluid

An unsteady numerical investigation of fluid-structure interaction in forced magnetohydrodynamic convection of a ferrofluid within a downward step configuration, aiming to analyze its influence on flow dynamics and heat transfer mechanisms is presented. The research explicitly incorporates the deformation of an elastic top wall under the combined effects of hydrodynamic, magnetic, and thermal forces. This approach enhances the understanding of the interplay between wall deformation and forced convection under dynamic magnetic fields, an aspect rarely addressed in existing literature. The study examines the impact of key physical parameters, including the Reynolds number (100 ≤ Re ≤ 200), Hartmann number (0 ≤ Ha ≤ 50), Cauchy number (10⁻⁷ ≤ Ca ≤ 10⁻³), magnetic field inclination angle (0°≤g≤60°), and nanoparticle volume fraction (0% ≤ φ ≤ 8%) on flow structure, heat transfer, and wall deformation. The numerical modeling is based on the arbitrary Lagrangian-Eulerian formulation, solving the coupled Navier-Stokes, energy, and structural displacement equations using the finite element method. The results reveal that increasing the Reynolds number enhances thermal agitation and vortex formation, leading to improved heat transfer, while a decrease in the Cauchy number amplifies these effects. Conversely, a higher Hartmann number strengthens Lorentz forces, suppressing flow motion and stabilizing the thermal boundary layer. Furthermore, the inclination angle of the magnetic field significantly influences wall deformation, altering the interaction between the ferrofluid and the elastic boundary.