Abstract

This talk is concerned with interfacial fluid mechanics in the context of solidifying liquids. Due to favorable downscaling with length, capillary effects are dominant for submillimetric objects and play a key role is a number of engineering and natural processes where they dictate the shape of drops, thin films, and coatings. As such, interfacial effects have been widely researched, albeit primarily in Newtonian fluids or in fluids whose constitutive law remains constant over time. In particular, the subtle interplay between hydrodynamics, solidification and the solid structures formed when harnessing capillary effects remain poorly understood. We will attempt to fill this gap of knowledge and study the physics of viscous jets and sheets in solidifying liquids. We will discuss experiments conducted with a model system, an elastomeric solution, so as to elucidate the competing phenomena at play in the formation of patterns and structures arising from interfacial flows and their subsequent or concomitant solidification. We will revisit classic fluid mechanics models, e.g. lubrication, and adapt them to situations where the flow is arrested in finite time. First, we will discuss droplet forming instabilities and show that the patterns they form can be engineered via the use of templates. New phenomena, e.g. self-templating, will be explored too. Second, we will revisit classic coating, drainage and imbibition problems and demonstrate that these flows can be used for materials design, e.g. fabricate soft robots. In fact, curing converts the flows we study into elastic solids, introducing the concept of “building with flows”.

https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/fluid-mechanics-webinar-series