Water-based ferrofluid flow and heat transfer over a stretchable rotating disk under the influence of an alternating magnetic field

Flow and heat transfer of water-based nanofluid over a stretchable rotating disk under the influence of an alternating magnetic field is investigated. The external magnetic field creates a hindrance in the flow and depends on the frequency of the alternating magnetic field. The frequency of an alternating magnetic field can increase or decrease the viscosity of the magnetic fluid in the flow. A set of nonlinear differential equations in the present theoretical model is solved numerically using the finite element method. Volume concentration, frequency of the alternating magnetic field, magnetic polarization force, and Prandtl number play an important role in the velocity and temperature distributions of iron/water nanofluid. A comparative study for velocity and heat transfer is presented for iron/water, nickel/water, and cobalt/water ferromagnetic nanofluid. The rotational viscosity enhances the heat transfer in nanofluid provided the magnetic field should be stationary.