Micrometer-sized droplet ejection from a millimeter-sized spherical water drop using a megahertz multiple-fourier horn ultrasonic nozzle

A new phenomenon on droplet ejection, namely, one large spherical water drop ejecting simultaneously a very large number of monodisperse micro droplets was observed and studied in detail. An ultrasonic nozzle with multiple-Fourier horns in resonance enables controlled excitation of megahertz Faraday waves on the spherical water surface which leads to the ejection of 3.5-4.4μm monodisperse droplets at a high rate (>10⁷ droplets per second). This is in stark contrast to the RayleighPlateau instability, which ejects one droplet at a time.