Navigation : Top / Research / Bubble Charasteristics and Gas Transfer in the Surf Zone

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* Introduction [#yc943917]

An accurate estimation of gas transfer velocity at the air-sea interface is very important to understand environmental mechanisms of the earth. A wind dependent gas transfer model by Liss and Merlivat model has widely used the last decade. The gas transfer velocity of the Liss and Merlivat model increases rapidly when the wind speed exceeds 13m/s. This rapid increase of gas transfer velocity is explained by several reasons such as enhancements of wind and breaking wave induced turbulence, breaking wave induced air bubbles, and sea spray. However, quantitative roles and detail mechanisms of the enhancement are not well known due to the lack of detail measurements. To understand the gas transfer enhancement in high wind speed region, the bubble mediate gas transfer is one of important phenomenon.
Ocean surface gravity wave propagation from offshore to shoreline is often regarded as a single phase flow using potential flow theories or the Navier-Stokes equation. Generally, the single phase flow approach to the ocean wave is successful for simulating wave transformation in the coastal area. However, waves steepen and break due to the bottom bathymetric effects in the near shore. The wave breaking create dense plumes of bubbles, and dissipates energy and momentum. An accurate estimate of bubble size and population distributions in the surf zone is important for understanding two-phase flow characteristics, solving engineering problems and environmental mechanisms of the coastal area. Recent photographic studies have illustrated the disintegration of entrapped air cavities divided into bubbles. However, there are unexplained aspects of the problem, such as enhanced bubble populations in salt rather than freshwater scale effects of void and bubble size distribution in the laboratory experiments, and the relation between void fraction and turbulence.

#ref(http://sauron.civil.eng.osaka-cu.ac.jp/~mori/images/background/oga2.jpg)
#ref(http://sauron.urban.eng.osaka-cu.ac.jp/~mori/research/bubble_surfzone/wave_breaking_small.jpg)

This project has bee started since 2001.
** Collaborators [#jf37a711]
- Hiroaki Kashima, OCU
- Satoshi Nakagawa, OCU

* Experimental Results [#f3a0a4b3]
- [[English]]
- [[Japanese]]
This project has bee started since 2004.

* Mathematical Modeling [#g51d0b4a]
- [[Japanese]]
* Results [#o312a93f]
** Experimental Results [#f3a0a4b3]
- [[English:http://sauron.urban.eng.osaka-cu.ac.jp/~mori/research/bubble_surfzone/JGR_bubble]]
** Mathematical Modeling [#g51d0b4a]

* References [#va25cfd4]

** This Project [#y4439ef3]
- Mori, N., T. Suzuki and S. Kakuno (2007) Noise of acoustic Doppler velocimeter data in bubbly flow, Journal of Engineering Mechanics, American Society of Civil Engineers, in press (will be apeared in January issue).
- Kashima, H., N. Mori and S. Kakuno (2006) `Temporal-spatial relationship between air bubbles and turbulence in the surf zone', Proceedings of the 30th International Conference on Coastal Engineering, ASCE.
- Mori, N., Kakuno, S., T. Suzuki, Y. Ohnishi (2005) `Experimental study on bubble and turbulence relations in the surf zone', Third Asia Pacific Coasts 2005: APAC2005, pp.1841-1856.

- Mori, N. 'Air Bubble Distribution induced by Wind Wave Breaking', Annual Conference of Japanese Society for Multiphase Flow 

** Basic Theories [#x6e0ae70]

-Van De Sande et al.
Jet break-up and air-entrainment by low velocity turbulent water jets
Chem. Eng. Sci., 31, 219-224, 1976
** Others [#r0f7f610]
- [[References of air-bubbles of surf zone breaking]]

Lewis and Davidson, Bubble Splitting in shear flow, Trans. Inst. Chem. Eng., 60, 283-291, 1982

Deane, G.B., Sound generation and air entrainment by breaking waves in the surf zone, J. Acoust. Soc. America, 102, 2671-2689, 1997

Thorpe, S.A., 1992: Bubble clouds and the dynamics of the upper ocean. Q. J. R. Meteorol. Soc. 118, 1-22.

General Experiments and Observations:

Nature 385, pp.52-55.

Optical Measurements by Camera:

Grant B. Deane, M. Dale Stokes, Scale dependence of bubble creation mechanisms in breaking waves, Nature418, 839 - 844 (22 Aug 2002) Article

Mark Loewen
Nature418, 830 (22 Aug 2002) News and Views

W. Kendall Melville, Peter Matusov
Distribution of breaking waves at the ocean surface
Nature417, 58 - 63 (02 May 2002) Letters to Nature

Optical Measurements by PDA:

David Lee Black and Mardson Q. McQuay.
Laser-based particle measurements of spherical and nonspherical particles.
International Journal of Multiphase Flow, 27:1333-1362, 2001.

M. Sommerfeld, D. Broder, and J. Kussin.
Recent developments and applications of non-intrusive optical techniques for the analysis of dispersed multiphase flow.
In Proccedings of 4th International Conference on Multiphase Flow, pages 1-12, 2001.

Shao Lee Soo.
Instrumentation for fluid particle flow.
William Andrew Publishing, NY, 1999.

Acoustic Measurements:

Timothy Leighton
Surf zone bubble spectrometry: The role of the acoustic cross section
J. Acoust. Soc. Am. 110, 2694 (2001)

David M. Farmer
Bubble size distributions in the wind driven surface layer
J. Acoust. Soc. Am. 100, 2840 (1996)

Herman Medwin
On counting ocean bubbles acoustically
J. Acoust. Soc. Am. 98, 2920 (1995)

Pandit AB; Varley J; Thorpe RB; Davidson JF (1992) Measurement of bubble size distribution: an acoustic technique. Chem Eng Sci 47: 1079-1089.

Ali R. Kolaini and Steve Means
Noise generation by breaking waves in the surf zone
J. Acoust. Soc. Am. 109, 2422 (2001)


Ali R. Kolaini and Jeffrey A. Nystuen
Characteristics of the low- and high-frequency ambient sound from breaking waves in the surf zone
J. Acoust. Soc. Am. 103, 2865 (1998)

Ali R. Kolaini
Sound radiation by various types of laboratory breaking waves in fresh and salt water
J. Acoust. Soc. Am. 103, 300 (1998)

Jeffrey A. Nystuen and Ali R. Kolaini
Exploring the surf zone using ambient sound
J. Acoust. Soc. Am. 102, 3103 (1997)

Ali R. Kolaini, Alexander M. Sutin, and Christopher M. Hobbs
Sound magnification due to the collective oscillations of bubble clouds: A resonance phenomenon
J. Acoust. Soc. Am. 100, 2806 (1996)

Yi Mao, Ali R. Kolaini, Xinwei Hao, and Pat B. Dandenault
Scattering of sound from laboratory breaking waves
J. Acoust. Soc. Am. 98, 2938 (1995)

Pat B. Dandenault, Ali R. Kolaini, and Yi Mao
Measurements of the scattering of sound from laboratory breaking waves
J. Acoust. Soc. Am. 96, 3232 (1994)

Gas Exchange:

S. Komori and R. Misumi.
The effecs of bubbles on mass transfer across the breaking air-water interface.
In M.A. Donelan, W.M. Drennan, E.S. Saltzman, and R. Wanninkhof, editors, Gas Transfer at Water Surfaces, pages 285-290. AGU, Washington DC, 2002.

P.S. Liss and L. Merlivat.
Air-sea gas exchange: introduction and synthesis.
In P. Buat-Menard, editor, The role of air-sea exchange in geochemical cycling, pages 113-27. Dordrecht, Reidel, 1986.

L. Merlivat and L. Memery. Contribution of bubbles to gas transfer across an air-water interface, 1985.

E.C. Monahan.
Occurrence and evolution of acoustically relevant subsurface bubble plumes and their associated, remotely monitorable surface whitecaps.
In B.R. Kerman, editor, Natural Physical Sources of Underwater Sound. Kluwer Academic Pub., Dordrecht, 1990.

Thorpe, S. A., 1982: On the clouds of bubbles formed by breaking wind-waves in deep water, and their role in air-sea gas transfer. Philos. Trans. Roy. Soc. London, Ser. A, 304.

** Others: [#i91c223f]