The role of fluid dynamics on the freezing process of impinging droplets

Droplet flow phenomena are found widespread in everyday life.

Coffee ring marks on a table-top, droplets of wine forming in a wine glass, surface cleaning of leaves through hydrophobicity and freezing rain on a pedestrian crossing are but a few examples.

The co-existing flow mechanisms taking place inside and outside the droplets are however not as easily distinguished and quantified.

This project will provide new means with which droplet phase change can be investigated, controlled and prevented, i.e. transformative in areas such as anti-icing, de-icing and detection systems.

Fundamental knowledge of how substrate material and patterning, external flow and internal convection influence the freezing process is furthermore crucial not only for disruptive innovations of anti-icing and de-icing mechanisms but also in processes such as polymerization and additive manufacturing.Previously developed numerical models and experimental set-ups show intriguing results regarding internal movement in water droplets as well as a distinct dependence of surface roughness on the initiation of solidification.

With funding to support a PhD student position together with the development of numerical and experimental methods including a small scale wind tunnel to complement the existing laser-based PIV set-up, this project will provide new, state-of-the-art, tools with which the fundamental physics behind freezing droplets can be examined.