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Elastocapillary flows
The deformation of elastic structures under capillary forces (elastocapillarity) and their interaction with fluid flow (elastohyrodynamics), are important in many biological, geophysical and engineering processes. To understand these phenomena, I propose three model systems of elastocapillary flows that will be presented using a combination of experiment, theory, and numerical simulation. First, I will present two model systems of surface-tension-driven flows into a gap between flexible boundaries (i.e. elastocapillary imbibition), with and without gravitational effects, to demonstrate how the presence of flexible boundaries leads to a departure from classical imbibition. A criterion for the coalescence of the boundaries (i.e. liquid capture) is established. Then, I will study the elastocapillary response of an array of elastic fibers interacting with a mist of droplets by considering a finite volume drop on a pair of two flexible fibers. The drop either remains compact without spreading or spreads into a liquid column that joins the fibers together. We find that there is a critical volume of liquid above which this spreading, hence fiber coalescence, does not occur and we identify another volume which maximizes spreading, thus liquid capture. For both the wetting and deformation of the substrates, universal rules are deduced from the geometric and material properties of the fibers and the volume of the drop. Further, I will apply these results to the drying of fiber arrays and show how the different liquid morphologies lead to distinct evaporation dynamics.