Nonlinear capillary systems with surfactant-laden interfaces

• Applicant: Professor Dr. Berend van Wachem
• Subject Area: Fluid Mechanics ; Mechanical Process Engineering
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 420239128

Surface-active substances adsorbed to fluid interfaces are omnipresent and understanding their subtle but often dominant influence is, consequently, of central importance for a vast amount of engineering applications and natural phenomena. Theoretical studies of the physicochemical hydrodynamics of capillary systems with surfactants have, so far, been predominantly limited to simple surfactants, cases without topology changes and small Reynolds numbers. As a result, a comprehensive understanding of the influence of surface viscosity and inertia, which is important in engineering applications ranging from bioengineering to manufacturing, in capillary systems including changes in interface topology remains elusive. This project studies the fundamental physical mechanisms associated with the nonlinear behaviour of surfactant-laden capillary systems, focusing on the subtle but important influence of surface viscosity, as well as the evolution of capillary instabilities and breakup. This will contribute a more detailed understanding of the interaction of surface viscosity and inertia with surface-tension-dominated interface motion, and its effect topology changes in capillary systems, over a wide range of length scales. To study these flows, we will develop new numerical methods for the simulation of interfacial flows with insoluble surfactants and surface viscosity in the remit of continuum mechanics, which will, integrated into state-of-the-art numerical simulation tools, provide a rational computational framework for the accurate modelling of surface-active substances.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Fabian Denner