Drops-on-Drops Thick Film Coating by Stable Viscous Electrostatic Jets(Fluids Engineering)

Hydrodynamic instability of a thin viscous film between two drops.

Linear stability analysis is employed to derive analytical expressions for the growth rate of disturbances applied to a thin plane-parallel film trapped between two drops. From these expressions, the band of unstable wavenumbers and the "most dangerous" wavenumber are identified for systems in the absence and presence of insoluble surfactant. Marangoni effects are shown to exert a stabilizing i...

Evolution and Breakup of Viscous Rotating Drops

We study the evolution of a viscous fluid drop rotating about a fixed axis at constant angular velocity Ω or constant angular momentum L surrounded by another viscous fluid. The problem is considered in the limit of large Ekman number and small Reynolds number. The analysis is carried out by combining asymptotic analysis and full numerical simulation by means of the boundary element method. We ...

Electrohydrodynamics of viscous drops in strong electric fields: numerical simulations

Weakly conducting dielectric liquid drops suspended in another dielectric liquid and subject to an applied uniform electric field exhibit a wide range of dynamical behaviours contingent on field strength and material properties. These phenomena are best described by the Melcher–Taylor leaky dielectric model, which hypothesizes charge accumulation on the drop–fluid interface and prescribes a bal...

Interaction of two deformable viscous drops under external temperature gradient

The axisymmetric deformation and motion of interacting droplets in an imposed temperature gradient is considered using boundary-integral techniques for slow viscous motion. Results showing temporal drop motion, deformations and separation are presented for equal-viscosity fluids. The focus is on cases when the drops are of equal radii or when the smaller drop trails behind the larger drop. For ...

On Toroidal Rotating Drops