Characterization of sound induced by bubbles released from nozzles

In an oil spill event, the leaked crude oil creates underwater sound through bubble oscillations and fluid jets. In this laboratory study, sound induced by bubbles in two types of oil leakage were simulated: a few bubbles and constant flow bubbles. We investigated sound emitted by bubbles released from nozzles, aiming to obtain the characteristics of the oil leakage from the recorded sound signals. For the few bubble case, the dependences of bubble size and frequency on the nozzle diameter were measured. A relation between the average size of bubble and acoustic frequency with the nozzle diameter was used to explain the measurements. In the case of constant flow bubbles, different flow rate was tested. The relation of acoustic energy with the flow rate was obtained from the experimental data. Bubble size distribution was obtained from the spectrum of recorded sound signals. The physical modeling of the bubble sound will be presented and discussed. [Funded by the Gulf Research Program of the National Academy of Sciences.]