Wind-Wave Generation on Restricted Fetches
COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS
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Wind-wave generation in lakes, rivers, bays, and reservoirs is generally limited by the geometry of the water body, which is often very irregular. Most approaches to this problem consider wave generation only in the direction of the wind with fetch lengths averaged over small arcs of large arcs. Donelan proposed wave generation on fetch lengths in off-wind directions with reduced wind forcing reduced by the cosine of the angle between the off-wind and wind directions for the Great Lakes. The model described in this report, NARFET, is based on the Donelan concept, allowing wave generation in off-wind directions. Expressions are developed for significant wave height and peak period as a function of fetch geometry and wind speed based on linear regressions of wave data collected on Puget Sound, Washington Fort Peck Reservoir, Montana Dension Reservoir, Texas and Lake Ontario. The mean wave direction is determined by maximizing the wave period. The equations differ from those given by Donelan, which were developed for the longer, more regular-shaped fetches of the Great Lakes. The NARFET model is quick and inexpensive runs on a personal computer, yet considers the complexity of fetch geometry.
- Hydrology, Limnology and Potamology