A Phase Field Modeling Study of the Rayleigh-Taylor Instability Subject to a Horizontal Electric Field

A numerical phase field model is developed to investigate the Rayleigh-Taylor instability (RTI) subject to a horizontal electric field. The model entails the simultaneous solution of the electric field equation and the Navier-Stokes equation for fluid flow coupled with the phase field model for the evolution of the fluid-fluid interface deformation and morphology. The in-house Fortran code was developed to enable the computing. Results show that, for pure dielectric fluids, the presence of the horizontal electric field induces polarization charges and produces a Korteweg-Helmholtz force which acts to suppress the RTI. For poorly conducting liquids, for which a leaky dielectric description is more appropriate. In this model, both polarization and free charges present. The effect of the free charge in this case depends on the specific values of λ_ε and λ_σ. For the fluids of λ_ε >1, it aggravates RTI if λ_σ<λ_ε, and suppresses that when λ_σ>λ_ε.