Significance and Limitations of Theoretical Models in Ferrohydrodynamics

ABSTRACT This paper examines the five fundamental models to study ferrohydrodynamics (FHDs). These models are important to study theoretically any physical phenomena of FHD flow. To yet, no researcher has examined the importance and limitations of these models. This study work is an attempt to present a complete set of equations for these models. This study also addresses the limitations and practical applicability of these models in FHDs. Neuringer–Rosensweig models are found to be suitable for cases where the applied magnetic field and the magnetization are parallel. The Jenkins model is important to deal with the problems related to lubrication since this model includes the role of material constants in the governing equations. The Shliomis model takes into account how fluid and magnetic particles interact when a magnetic field is present. This model is important for the problems related to rotational viscosity and considers the role of time‐varying magnetic fields. Berkovsky's nonequilibrium magnetization model is useful when the magnetic field is not in an equilibrium position. In the couple stress models of Berkovsky, the imposed magnetic field interacts not only with magnetic particles by means of force as well as torque interactions. Researchers do not use it much, nevertheless, because of its high nonlinearity and difficulties. To increase the effectiveness of theoretical models in FHDs, these models should take into account variations in the volume concentration, size distribution of magnetic particles, chain formation effect, and stability of magnetic fluid.