Bubble injection under breaking waves
By:  James B. Tannahill
Publisher: Naval Postgraduate School; Available from National Technical Information Service
Published: 1996
Place of publication: Monterey, Calif; Springfield, Va
Language: eng
Number of pages: 41
Description: Wave energy dissipation due to bubble penetration and inferred turbulent penetration from      breaking waves in the surf zone is related to the total energy of dissipation. Bubble injection is      inferred from void fraction measurements obtained using a 2.3 meter vertical array of eight      conductivity sensors extending from the bottom through the water surface. Potential energy      and dissipation associated with bubble injection are calculated and compared with total wave      dissipation. Total wave dissipation is calculated from the energy flux balance measured using      an array of seven pressure sensors in the surf zone. Percent of total wave potential energy of      the bubbles due to spilling breakers is on the order of 0.18% to 0.62%, consistent with past      measurements in the surf zone. Percent of the bubble potential energy dissipation rates to total      wave dissipation in the cross shore direction is on the order of 8% to 20%. The potential      energy dissipation is largest immediately after injection, decaying exponentially after that.      Bubble potential energy dissipation results within 1.2 seconds even for void fraction events      greater than 36% and usually in less than 1.0 seconds. Energy dissipation was found linearly      related (0.95 correlation coefficient) with the ratios of wave height to water depth, a measure      of the percent of breaking waves within the surf zone.
Notes: Thesis advisor(s): Edward B. Thornton, T.P. Stanton.

"December 1996."

Thesis (M.S. in Meteorology and Physical Oceanography) Naval Postgraduate School, December 1996.

Includes bibliographical references (p. 39-40).

Approved for public release; distribution unlimited.

Also available online.

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US Navy (USN) author.

dk/dk cc:9116 6/12/97.