Enhancing Rayleigh-regime liquid jet breakup with MHz-order acoustic waves

We present a new device that effectively reduces the breakup of cylindrical Rayleigh-regime liquid jets in quiescent air. The device is made of lithium niobate, a piezoeletric material, to convert input electrical power into oscillation. A 10x10 mm crystal with a through hole of 1 mm in diameter placed at the outlet of the liquid's nozzle, the device creates 7 MHz acoustic waves that disrupt the stability of the jet. We show its effectiveness over a range of different input powers and Weber and Ohnesorge numbers. Furthermore, we show modelling results in COMSOL and equations that describe this new instability mechanism. This opens new doors for droplet-on-demand applications.