ELECTROHYDRODYNAMIC INSTABILITY OF A STREAMING DIELECTRIC VISCOUS LIQUID JET WITH MASS AND HEAT TRANSFER

Abstract

The current paper investigates the electrohydrodynamic (EHD) instability of a streaming dielectric liquid jet. The inner medium is occupied by an incompressible Newtonian viscous fluid. Simultane-ously, the outer medium is filled with an incompressible gas. The system is pervaded by a uniform axial electrostatic field. The mass and heat transfer phenomenon is taken into account. In order to relax the mathematical manipulation, a simplified modulation of this system is adopted. The normal modes analysis is utilized to solve the boundary-value problem and to judge the linear stability of the system. A non-dimensional treatment reveals two non-dimensional numbers:Weber and Ohnesorge. The linear stability analysis resulted in a very complicated transcendental dispersion equation. The same numbers are considered with regard to the temporal and spatial increase of both frequency and modulation. The influences of various physical parameters in the stability profile are exercised as well. It is found that the velocity ratio between gas to liquid has a dual role in the stability profile. Moreover, the Weber number has a destabilizing effect, which produces a higher growth rate and, thus, shorter breakup time. In addition, the presence of the electric field as well as the mass and heat transfer stabilize the viscous liquid jet. Furthermore, the viscous effect as indicated by the Ohnesorge number has a stabilized influence. The present work gives a good foundation of the investigation of the instability and breakup of a viscous liquid jet with electric field effect and mass and heat transfer existence.