DOI: 10.21276/sjpms.2016.3.4.11

Pages: 173-177

This paper investigates the influence of an external magnetic field on the interfacial stability of viscous fluid configurations subjected to differential motion or thermal forcing. The analysis is carried out within the framework of linear magnetohydrodynamics (MHD), where small perturbations at the interface between viscous fluid layers are examined under the combined effects of viscosity, inertia, and magnetic stresses. A general dispersion relation is derived by incorporating the Lorentz force into the momentum balance, allowing the stability characteristics to be expressed in terms of key nondimensional parameters such as the Reynolds number, Hartmann number, and fluid viscosity ratio. The results show that the presence of a magnetic field suppresses interfacial disturbances by damping velocity fluctuations and reducing the growth rate of unstable modes. The stabilizing effect becomes more pronounced with increasing field strength and electrical conductivity, though it is sensitive to boundary conditions and the orientation of the applied field. The findings offer insight into the behavior of magnetized viscous layers in astrophysical plasmas, metallurgical processes, and engineering systems where control of interfacial instabilities is crucial.