Measurements of the diameter of rising gas bubbles by means of the ultrasound transit time technique

This study presents ultrasound transit time technique (UTTT) measurements of single Ar bubbles rising in Galinstan under an applied magnetic field. Two setups were used to analyze the bubble rise, which led to differently oriented zig-zag trajectories. UTTT is able to visualize the bubble trajectory and to measure the variations of the apparent bubble diameters associated with the zig-zag trajectory. Due to the straightening of the bubble trajectories with increasing magnetic field, an increase of the apparent bubble diameter was detected.