DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS MD
This report begins with a brief review of microbubble research, with emphasis on Navy needs. The existence of microbubbles in the ocean and the need for a theory to explain their presence are discussed. The principal equations describing the acoustic effects of microbubbles are given. The design, operating principles, and evaluation of a microbubble spectrum analyzer, developed by Vitro Labs., are described. The prototype instrument uses variations in acoustic velocity and attenuation to measure the microbubble size distribution in the ocean over the size range of 1- to 30- micrometer radius. The evaluation consisted of 1 a laboratory calibration of the electronic circuits 2 a laboratory acoustic calibration where the acoustic properties of a water sample were changed and 3 a field test of the instrument in the Severn River.