Abstract:

The unsteady magnetohydrodynamical (MHD) free convection flow of an incompressible, electrically conducting hybrid nanofluid within a vertical cylindrical geometry is investigated, incorporating the effects of thermal radiation, viscous dissipation, and internal heat generation. The system is subjected to a time-periodic boundary temperature condition. The Laplace and finite Hankel transforms are used to derive the exact solutions for the velocity and temperature distributions. The effects of various key physical parameters, including the Richardson number, the Eckert number, the radiation parameter, the heat source parameter, and the nanoparticle volume fraction, are considered. The numerical results reveal that increasing the volume fraction significantly enhances the thermal conductivity and temperature, while the magnetic field intensity and viscous dissipation strongly influence the fluid motion and heat transport. Additionally, the pulsating boundary conditions produce distinct oscillatory behaviors in both the velocity and temperature fields. These findings provide important insights into optimizing the heat transfer performance in cylindrical systems such as electronic cooling modules and energy storage devices operating under dynamic thermal conditions.

Key words: forced convection, lid-driven cavity, streamline, finite element method (FEM)