Dynamics of fiber-laden drops

• Applicants: Professor Dr. Steffen Hardt; Gregory Lecrivain, Ph.D.
• Subject Area: Fluid Mechanics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 492454247

The proposed project focuses on the unsteady behavior of drops containing filaments or fibers, here referred to as fiber-laden drops. In such ternary systems, structural, capillary, and fluid dynamics are all intertwined. Up to now, the vast majority of studies involving fiber-laden drops that have been conducted were focused on stationary configurations. The unsteady behavior of fiber-laden drops, however, has received much less attention. The project, based on a close interaction between experiments and simulations, will focus on two key scenarios involving fiber-laden drops. First, the low-energy impact of fiber-laden drops on a solid surface will be analyzed, with the goal to clarify how the fiber inside the drop influences the dynamics and especially the rebound of the drop. Second, the generation of fiber-laden drops at a channel junction will be studied. One goal of this last investigation will be to establish a well-controlled high-throughput process with drops containing a precise number of fibers. The experimental investigations will be accompanied by the development of a numerical model capable of handling the fast dynamics of fiber-laden drops. The model is based on a hybrid Eulerian/Lagrangian description, where a fiber is represented by a chain of interacting spherical beads. For each of the two key scenarios, the dynamic regimes in a parameter space spanned by the dimensionless numbers of the problem will be explored based on a close interaction between experiments and simulations.

• DFG Programme: Research Grants