Friction velocity scaling in wind wave generation

✍ Scribed by Peter A. E. M. Janssen; Gerbrand J. Komen; Willem J. P. Voogt

• Publisher: Springer
• Year: 1987
• Tongue: English
• Weight: 423 KB
• Volume: 38
• Category: Article
• ISSN: 0006-8314
• DOI: 10.1007/bf00121552

✦ Synopsis

This note is devoted to the problem ofthe appropriate scaling ofparameters relevant for sea waves, such as wave height, peak frequency, duration, and fetch. In the past, the growth of sea waves has often been analysed in terms ofthe wind velocity at a fixed height, despite the fact that many authors have stressed the importance of scaling with the friction velocity. This problem would be immaterial if the ratio between the friction velocity and the wind speed at a fixed height were a constant. There is, however, ample evidence that this ratio increases with wind speed , in agreement with dimensional considerations by Chamock (1955) on the friction height. As a result, the scaling problem is an important one. In this note we conjecture that the correct procedure is to scale wave parameters with friction velocity, and we discuss experimental evidence for the correctness of this conjecture. Comparing two independent datasets ('JONSWAP' and 'KNMI'), we find some evidence supporting our ideas. Further confirmation remains desirable, however, and suggestions are made as to how this might be obtained.