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On the variation and growth of wave-slope spectra in the capillary-gravity range with increasing wind

Published online by Cambridge University Press:  11 April 2006

Steven R. Long
Affiliation:
Center for Marine and Coastal Studies, North Carolina State University, Raleigh Present address: NASA Wallops Flight Center, Wallops Island, Virginia 23337.
Norden E. Huang
Affiliation:
Applied Science Directorate, NASA Wallops Flight Center, Wallops Island, Virginia 23337

Abstract

A new laser device has been used to make direct wave-slope measurements in the capillary-gravity range. Owing to the design principles, the digital nature of the system and the use of a laser beam as a probe, the earlier problems of intensity variations and meniscus effects were avoided. Using this new technique, wave-slope spectra both down and across the channel were obtained for different wind conditions, along with corresponding mean-square slope values. Comparisons are made with existing data. The results indicate that a quasi-equilibrium state may exist for each wind speed and that it increases in intensity with increasing wind, which may imply an asymptotic nature for the equilibrium-range coefficient Caa. From the data, two significant frictional velocities, 17.5 and 31 cm/s respectively, are identified as critical values for different ranges of wave development.

Type
Research Article
Copyright
© 1976 Cambridge University Press

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