To eject a droplet from a dampened, damped beam

At the scale of small insects, additional mass such as moisture deposited on wings from rain and dew fall alters flight dynamics. Successful flight, therefore, requires that surfaces are free of debris. Drawing from drying behaviors witnessed in mosquitoes, we investigate the release of droplets from flexible, high-amplitude cantilever beams at the mesoscale. These beams are sinusoidally displaced at their base across 85-400 Hz, producing surfaces accelerations of 2-120 gravities at droplet release. We observe three principle droplet ejection modes: normal to beam ejection, tangential to beam ejection and droplet volume reduction through pinch-off. Experiments show that ejection modes are dependent on droplet and cantilever properties, and input motion in this highly coupled system. Predictions of ejection modes are accomplished by application of Euler elastica theory and droplet adhesion forces.