Anisotropic growth dynamics of liquid bridge during droplet coalescence under acoustic levitation

This study investigates the anisotropic growth dynamics of liquid bridges during droplet coalescence under acoustic levitation. Numerical and experimental results revealed that the early-time evolution of aliquid bridge follows a scaling law d∼t0.5 in the inertial regime, with different prefactors for horizontal and vertical growth. Sound-field simulation results indicate that the high aspect ratio of the liquid bridge is influenced by the nonuniform distribution of acoustic radiation pressure, leading to significant differences in the curvature of the bridge neck between the horizontal and vertical directions, which in turn affects the Laplace pressure distribution. The interplay between acoustic radiation pressure and Laplace pressure is analyzed, with Laplace pressure identified as the dominant driving force for bridge growth. A dimensionless parameter is introduced to quantify the contributions of acoustic and capillary forces, shedding light on understanding the mechanisms of anisotropic growth of liquid bridges under acoustic levitation. locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon locked icon Physics Subject Headings (PhySH)Drop coalescenceLiquid bridgesAcoustic levitation