HIGH-SPEED BUBBLE SIZING USING THE DOUBLE FREQUENCY TECHNIQUE FOR OCEANOGRAPHIC APPLICATIONS

A high-speed bubble sizing technique has been developed that should have the capability of accurately determining bubble populations during breaking waves. The system developed to date was able to acquire an average bubble spectrum from 2.5 to 6 kHz in 0.1 s. Through the use of a double frequency technique, there would be very little or no contribution from nonresonant bubbles at each frequency of interest. The results of the system were compared to the data obtained by listening to ambient bubble noise with a transducer and from photographic population counts.