Nonlinear behavior of electrohydrodynamic flow in viscoelastic fluids

This paper presents a numerical study of electrohydrodynamic flow for the problem of electroconvection in a viscoelastic dielectric liquid subjected to unipolar injection. The nonlinear evolution of flow for diverse characteristic Weissenberg numbers is examined in detail. The influences of elasticity on the flow pattern, oscillation amplitude, current transfer, and power-law spectral scaling accompanying oscillatory flow are also investigated. The results demonstrate that the effect of viscoelasticity leads to hydrodynamic behaviors that are absent in Newtonian fluids. The transition sequences to the chaos of electroconvection in viscoelastic fluids are quite different from those in Newtonian fluids, and the elasticity precipitates the onset of chaos. An asymmetric steady flow pattern resulting from elasticity is observed in a perfectly symmetric geometry. The fluctuation amplitude of fluid motion is found to be suppressed for weakly elastic fluids but amplified when the fluid elasticity exceeds a certain threshold. For viscoelastic fluids, electric current transfer is reduced in most cases, but for weakly elastic fluid, it may be enhanced.