Abstract
The minimum value of wind stress under which the flow velocity in short wind waves exceeds the phase speed is estimated by calculating the laminar boundary layer flow induced by the surface tangential stress with a dominant peak at the wave crest as observed in previous experiments. The minimum value of the wind stress is found to depend strongly onβ, the ratio of the flow velocity just below the boundary layer and the phase speed, but weakly onL, the wavelength. For wind waves previously studied (β=0.5,L=10 cm), the excess flow appears when the air friction velocityu * is larger than about 30 cm sec−1. The present results confirm that the excess flow found in my previous experiments is associated with the local growth of a laminar boundary layer flow near the wave crest.
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Okuda, K. Internal flow structure of short wind waves. Journal of the Oceanographical Society of Japan 40, 46–56 (1984). https://doi.org/10.1007/BF02071208
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DOI: https://doi.org/10.1007/BF02071208