Unified electro-magneto-fluid dynamics (EMFD): A survey of mathematical models

Fluid flow influenced by electric and magnetic fields has classically been divided into two separate, simplified categories: electro-hydrodynamics (EHD) studying flows under the influence of an electric field with free electric charges and no magnetic field, and magneto-hydrodynamics (MI-ID) studying flows under the influence of a magnetic field and no free electric charges or electric fields. This division was necessary to reduce the extreme complexity of the coupled system of Navier-Stokes, Maxwell's and constitutive equations describing combined electro-magneto-hydrodynamic (EMFD) flows [G. S. Dulikravich and S. R. Lynn, Unified electro-magneto-fluid dynamics (EMFD): introductory concepts. Int. J. Non-Linear Mechanics 32, 913-922 (1997)]. In this paper, the unified EMFD theory is compared with classical EHD and MHD models. This reveals the inconsistencies and shortcomings of classical formulations and allows discussion of the relative importance of terms describing the electro-magnetic force, electric current and heat transfer. (C) 1997 Elsevier Science Ltd.