Accession Number : ADA325670

Title :   Acoustical Emission from Bubbles and Dynamics of Bubbles and Bubble Clouds.

Descriptive Note : Final rept. 1 Mar 91-30 Sep 96,

Corporate Author : CALIFORNIA UNIV SAN DIEGO LA JOLLA OFFICE OF CONTRACT AND GRANT ADMINISTRATIO N

Personal Author(s) : Longuet-Higgins, Michael S.

PDF Url : ADA325670

Report Date : JAN 1997

Pagination or Media Count : 17

Abstract : The aim of the research was to further our understanding of the natural sources of sound near the ocean surface, which are known to be due mainly to oscillating bubbles and bubble clouds. A theory has been given for the damping of bubble oscillations by nonlinear coupling between different modes of oscillation of a spherical bubble. Some experimental confirmation was found by later workers. A simple statistical model has been proposed for the initial bubble sizes from breaking waves, which also has received experimental support. A direct method of calculating wave-generated ripples has been proposed, which accounts quantitatively for observations. It has been shown that such capillary waves can be important sources of vorticity, and hence of turbulence, near the crests of short gravity waves, and can lead to a certain a type of wave breaking. Other investigations concern the dynamics of capillary-gravity waves of solitary type on deep water, the emission of sound by the controlled release of bubbles from an underwater nozzle, and the formation of inward-going jets in bubble splitting or bubble collapse. Such jets are shown to be dynamically similar to those occurring in standing surface waves, or waves breaking against a harbor wall. Several other aspects of wave breaking have also been investigated.

Descriptors :   *EMISSION, *OCEAN SURFACE, *DAMPING, *BUBBLES, *ACOUSTIC EMISSIONS, MATHEMATICAL MODELS, SURFACE WAVES, VORTICES, NONLINEAR SYSTEMS, SOUND, STATISTICAL ANALYSIS, OSCILLATION, UNDERWATER, GRAVITY WAVES, STANDING WAVES, CAPILLARY WAVES.

Subject Categories : Acoustics
      Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE