An air bubble detaches from an underwater nozzle 6 mm in internal diameter,
captured at 4100 frames per second in Swinburne's Energy Transformation
Laboratory. At the instant of detachment, the sudden change in interface
topology causes a slight expansion or compression of the air trapped in the
newly formed bubble. This causes the bubble volume to ring and emit sound.
Bubble-formation sounds account for much of the noise associated with moving
water and are being investigated for industrial and oceanic measurements.
This work is presented in “Amplitudes of bubble sound emissions depend on formation mechanism” at the 25th Australasian Fluid Mechanics Conference (AFMC2026), held in Christchurch, New Zealand, from 6–10 December 2026. References: Nelli et al 2022, JASA-EL 2, 054002. Nelli et al 2024, JASA 156, 350–358. Nelli et al 2025, JASA 158, 1443–1450.