The development of stationary patterns on a thin polymer surface subject to an electric field is studied by means of the hexagonal-planform weakly nonlinear stability analysis and numerical simulations. The time evolu...The development of stationary patterns on a thin polymer surface subject to an electric field is studied by means of the hexagonal-planform weakly nonlinear stability analysis and numerical simulations. The time evolution of the interface between the air and the polymer film on the unbounded spatial domain is described by a thin film equation, incorporating the electric driving force and the surface diffusion.The nonlinear interfacial growth includes the amplitude equations and superposition of one-dimensional structures at regular orientations. The pattern selection is driven by the subcritical instability mechanism in which the relative thickness of the polymer film plays a critical role.展开更多
In this study, the breakup of a melt jet into a viscous medium is investigated in the presence of an intense electric field. Fragmentation of the melt jet occurs due to both hydrodynamic and electrohydrodynamic （EHD...In this study, the breakup of a melt jet into a viscous medium is investigated in the presence of an intense electric field. Fragmentation of the melt jet occurs due to both hydrodynamic and electrohydrodynamic （EHD） forces within two kinds of silicone oil of different viscosities. The size and shape characteristics of the produced particles have been studied using SEM images, and the particle size distributions were found to exhibit considerable variations when a voltage was applied and when both the viscosity and temperature of the base fluid were changed. The morphologies of the particles were also affected by the same parameters. For instance, by applying EHD force, significant enhancements in size reduction and increased roundness of the particles occurred. The breakup process of the melt jet was found to be dominant by hydrodynamic or electrohydrodynamic instabilities, depending on the situation. Governing mechanisms （instability） in the cases of pure hydrodynamic and electrohydrodynamic fragmentations are discussed.展开更多
文摘The development of stationary patterns on a thin polymer surface subject to an electric field is studied by means of the hexagonal-planform weakly nonlinear stability analysis and numerical simulations. The time evolution of the interface between the air and the polymer film on the unbounded spatial domain is described by a thin film equation, incorporating the electric driving force and the surface diffusion.The nonlinear interfacial growth includes the amplitude equations and superposition of one-dimensional structures at regular orientations. The pattern selection is driven by the subcritical instability mechanism in which the relative thickness of the polymer film plays a critical role.
文摘In this study, the breakup of a melt jet into a viscous medium is investigated in the presence of an intense electric field. Fragmentation of the melt jet occurs due to both hydrodynamic and electrohydrodynamic （EHD） forces within two kinds of silicone oil of different viscosities. The size and shape characteristics of the produced particles have been studied using SEM images, and the particle size distributions were found to exhibit considerable variations when a voltage was applied and when both the viscosity and temperature of the base fluid were changed. The morphologies of the particles were also affected by the same parameters. For instance, by applying EHD force, significant enhancements in size reduction and increased roundness of the particles occurred. The breakup process of the melt jet was found to be dominant by hydrodynamic or electrohydrodynamic instabilities, depending on the situation. Governing mechanisms （instability） in the cases of pure hydrodynamic and electrohydrodynamic fragmentations are discussed.
