Acoustic nucleation and bubble jetting inside a small droplet (en)
* Presenting author
Abstract:
Recently, we have reported results on the formation of a jetting bubble in the proximity of a curved free boundary given by the hemi-spherical top of a water column or a drop sitting on a solid plate. As a natural extension of that work, we now present a series of experimental results and simulations on the nucleation of laser induced bubbles inside a liquid droplet of a millimetric size in free fall motion. In this case the drops were released from a height of around 20 cm, acquiring a speed of around 2 m/s at the instant were the laser bubble is nucleated. Under these circumstances the bubbles remained almost spherical and thus are subjected to the influence of a free boundary in every direction. This represents an interesting scenario for the study of jetting bubbles, considering that the laser bubble can be generated at different positions inside the drop, and the intrinsic curvature of the liquid surface permits to observe the drop and particularly the bubble interior in a clear way. We have also investigated the nucleation of acoustic bubbles in tridimensional clusters induced by the rarefaction wave and the onset of a Rayleigh-Taylor instability on the drop surface.