Instability modes of fluid interfaces under normal AC electric fields

• Applicant: Professor Dr. Steffen Hardt
• Subject Area: Fluid Mechanics
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 422719952

Based on preliminary theoretical work, it is proposed to study the instability modes of fluid interfaces under application of a normal electric field. The term "fluid Interface" refers to an interface between two immiscible fluids, an electrolyte and a dielectric fluid. The dielectric fluid may either be a gas or a liquid. The main focus of the project will be on spatially homogeneous AC electric fields. The instability modes of the fluid interface will be studied in terms of their spatial structure and oscillation frequency. The threshold field strength needed to trigger the instability will be determined. After initial studies with clean fluid interfaces, the studies will be extended to interfaces covered with surfactants or particles. Specifically, it is expected that surfactant or particle-covered fluid interfaces exhibit instability modes that are qualitatively and quantitatively different from those of clean interfaces. Furthermore, it is planned to extend the existing theory in specific directions. The proposed work may have implications for the controlled generation of small droplets induced by electric fields and for the structuring of liquid films via self-organization.

• DFG Programme: Research Grants