Instrumentation for the measurement of void-fraction in breaking waves: laboratory and field results

Author

Lamarre, Eric ; Melville, W. Kendall

Author_Institution

Dept. of Civil Eng., MIT, Cambridge, MA, USA

Volume

17

Issue

2

fYear

1992

fDate

4/1/1992 12:00:00 AM

Firstpage

204

Lastpage

215

Abstract

The authors report on the development and use of an impedance probe to measure the volume fraction of air (void-fraction) in bubble plumes generated by breaking waves. The void-fraction gauge described was found to be most useful in the initial period after breaking when large void-fractions prevail. The authors describe the instrumentation at length and report on its use in the laboratory and in the field. The instrument is found to be capable of rendering the space-time evolution of the void-fraction field from controlled laboratory breaking waves. Field results show measurements of void-fractions (up to 24%) which are several orders of magnitude greater than time averaged values previously reported. Preliminary measurements show that the fraction of breaking waves per wave is dependent on significant wave height and wind speed. The dependence on wind speed is compared with data of previous investigators. Underwater video photography from the field shows the formation and evolution of distinct bubble plumes and the presence of large bubbles (at least 6-mm radius) generated by breaking

Keywords

ocean waves; oceanographic equipment; 6 mm; air volume fraction; breaking waves; bubble plumes; impedance probe; underwater video photography; void fraction measurement; void-fraction gauge; Instruments; Laboratories; Ocean temperature; Probes; Sea measurements; Sea surface; Time measurement; Velocity measurement; Volume measurement; Wind speed;

fLanguage

English

Journal_Title

Oceanic Engineering, IEEE Journal of

Publisher

ieee

ISSN

0364-9059

Type

jour

DOI

10.1109/48.126977

Filename

126977