Fiber dynamics at a fluidic interface

Motivations

At submillimetric scales, the capillary forces become increasingly important and so thin and elastic fibers can easily deform or even break. This mechanism has for instance critical implication in microalgae flotation. By employing advanced numerical modelling techniques, we aim to investigate the dynamic behavior of long elastic fibers interacting with bubbles or droplets. One area of interest is the full encapsulation of the drop an extremely long flexible fiber.

Development of a numerical model for fiber-droplet dynamics

The core of this project lies in the development of a robust numerical model that simulates the dynamic interaction of fibers with bubbles or droplets. This model is developed using a hybrid Eulerian-Lagrangian framework, which resolves the deformation of elastic fibers and the surface tension forces acting on the droplet with high precision. It is done by decomposing the fiber into a chain of spherical beads which are interconnected by a virtual beam (Figure 1). The model captures the fiber bending, stretching, and twisting under the action of capillary forces, allowing for a deeper exploration of dynamic regimes and providing insights into the parameter spaces that govern fiber-drop interactions.

By resolving both quasi-static and dynamic configurations, the model provides a detailed understanding of fiber-droplet systems that would be challenging to achieve through experiments alone. This project involves a close collaboration with the Technical University of Darmstadt, where experimental studies are conducted to validate and refine the numerical model. The insights gained from our model can be directly applied to optimize processes like microalgae flotation, oil-water separation, and interface stabilization in experimental setups.

Funding

Supported by the German Research Foundation (Deutsche Forschungsgemeinschaft) under project number 4145129011.

Publications

Radhakrishnakumar, S., Bauer, L., Hardt, S., Hampel, U. and Lecrivain, G. (2024, September 16). Dynamic Behaviour of Fibre-Laden Drops. 1st European Fluid Dynamics Conference, Aachen, Germany.
Radhakrishnakumar, S., Hampel, U. and Lecrivain, G. (2025) Numerical Methods for the Resolved Simulation of Particle Transport at Fluidic Interface, Manuscript submitted for publication.
Lecrivain, G., Grein, T. B. P., and Yamamoto, R., Hampel, U. and Taniguchi T. (2020). Eulerian/Lagrangian formulation for the elasto-capillary deformation of a flexible fibre, Journal of Computational Physics, 409, 109324.