On the mechanism of dendritic fragmentation by ultrasound induced cavitation

•Interaction between cavitation bubbles and dendrite was observed in situ.•A model was developed to characterize the cavitation induced fragmentation.•The equivalent pressure induced by cavitation bubbles were estimated.•Geometry parameters of the dendrite influence its melting/growth behavior. A dedicated solidification device and high speed camera were used to capture dendritic fragmentation of pure succinonitrile (SCN) induced by oscillating ultrasonic bubbles. Theoretical analysis of the melting behavior of the dendrite was performed based on local solidification thermodynamics. The dendritic growth or the evolution of the solid-liquid interface is closely related to both thermodynamics of the cavitation bubble and the local geometry of the dendrite. Accordingly, for the first time, a dimensionless scaling formulation was developed by fitting both theoretical and experimental data to determine the variational pressure exerted by the cavitation bubble.