Measurements of bubble plumes and turbulence from a submarine |
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| Authors: | T. Osborn D.M. Farmer S. Vagle S.A. Thorpe M. Cure |
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| Affiliation: | 1. Department of Earth and Planetary Sciences , The Johns Hopkins University , Baltimore, Maryland, 21218;2. Institute of Ocean Sciences , Patricia Bay, Sidney, British Columbia, V8L 4B2;3. Department of Oceanography , The University of Southampton , Southampton, SO9 5NH, United Kingdom |
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| Abstract: | Abstract An experiment using turbulence probes and an array of side‐scan and vertically pointing pencil beam sonars mounted on the U.S. submarine Dolphin was carried out to measure turbulence in near‐surface regions of acoustic scattering, in particular, those caused by subsurface bubbles produced by breaking wind waves. The dataset collected during winds of 5–9 m s?1 reveals the banded patterns of bubbles associated with Langmuir circulation, even though no surface manifestations were visible. A forward‐pointing side‐scan sonar determined the “age” of bubble clouds after their generation by breaking waves. There is enhanced turbulent dissipation in the bubble clouds, and the dissipation rate close to the surface exceeds that predicted using conventional calculations based on the law of the wall and buoyancy flux. The correspondence between bubbles and turbulence implies a horizontally patchy turbulent structure near the surface. Below the base of the bubble clouds the distance between turbulent patches increases and is much greater than that of the bubble clouds. The submarine provides an excellent platform for multi‐sonar near‐surface studies. |
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