Vortex generation due to multiple localized magnetic fields in the hybrid nanofluid flow - A numerical investigation

Heliyon. 2023 Jul 4;9(7):e17756. doi: 10.1016/j.heliyon.2023.e17756. eCollection 2023 Jul.

Abstract

Vortices capture the attention of every scientist (as soon as they come into existence) while studying any flow problem because of their significance in comprehending fluid mixing and mass transport processes. A vortex is indeed a physical phenomenon that happens when a liquid or a gas flow in a circular motion. They are generated due to the velocity difference and may be seen in hurricanes, air moving across the plane wing, tornadoes, etc. The study of vortices is important for understanding various natural phenomena in different settings. This work explores the complex dynamics of the Lorentz force that drives the rotation of nanostructures and the emergence of intricate vortex patterns in a hybrid fluid with Fe3O4-Cu nanoparticles. The hybrid nanofluid is modeled as a single-phase fluid, and the partial differential equations (PDEs) that govern its behavior are solved numerically. This work also introduces a novel analysis that enables us to visualize the flow lines and isotherms around the magnetic strips in the flow domain. The Lorentz force confined to the strips causes the spinning of hybrid nanoparticles, resulting in complex vortex structures in the flow domain. The results indicate that the magnetic field lowers the Nusselt number by 34% while raising the skin friction by 9%. The Reynolds number amplifies the influence of the localized magnetic field on the flow dynamics. Lastly, the nano-scaled structures in the flow enhance the Nusselt number significantly while having a minor effect on the skin friction factor.

Keywords: Hybrid nanofluids; Localized magnetic field; Reynold number; Single-phase model; Vortex.