Factors affecting dynamic electrical manipulation of menisci

The dynamics of a conductive meniscus subjected to an external field are examined with a view toward drop-on-demand applications. A low-order model suitable for exploring parametric effects is developed. Equilibrium and stability criteria are derived for the purpose of estimating electric field requirements. The criteria are expressed in terms of dimensionless pressures due to electric stress, gravity, and hydrostatic head, normalized to surface tension pressure. Eigenvalues of the linearized model yield a formula for characteristic frequency analogous to Rayleigh´s formula for a free drop and, in addition, indicate that most liquids will show underdamped behavior. Requirements for critical damping are derived and illustrated with root locus plots