The dynamics of vertical coalescence of acoustically levitated droplets

Mobility manipulation of liquid droplets is an important task of digital imicrofluidics. Acoustic levitation has revolutionised the contactless manipulation of liquid droplets for various applications. Acoustic levitation technique can be effectively used to manipulate droplets to obtain their coalescence. This paper reports a unique, versatile, and material-independent approach for the vertical coalescence of the droplets suspended in an acoustic levitator. The acoustic power of the levitator is carefully engineered to obtain vertical coalescence of two liquid droplets. Water, 20