Underwater bubble sizing using a pulsed double frequency technique

A pulsed double frequency technique has been developed for detecting and sizing underwater air bubbles. The technique permits little or no contribution from nonresonant bubbles at each frequency of interest and thus provides an accurate estimate of the bubble sizes present. Evaluation of the system was made through tests in a small pool at ranges as far as 2 m. The results obtained with the system were compared to data obtained through passive listening.