Computer Program NARFET- Wind-Wave Generation on Restricted Fetches
Abstract
The purpose of this technical note is to predict significant wave height, peak period, and mean direction for narrow or restricted fetches. Wind-wave generation in lakes, rivers, bays, and reservoirs is generally limlted 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 (Shore Protection Manual (SPM) 1984) or large arcs (Savllle 1954). Donelan (1980) proposed wave generatlon on fetch lengths in offwind directions with reduced wind forcing (reduced by the cosine of the angle between the off-wlnd and wind directions) for the Great Lakes. The NARFET model (Smith 1989) is based on the Donelan concept, allowlng wave generation in off-wind directions. Smith developed expressions for wave height and 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), Denlson Reservoir (Texas-), and Lake Ontar i o. The mean wave d I rect ion is determined by maximizing the wave period. These 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 PC), yet considers the comlplexity of fetch geometry.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1989
- Accession Number
- ADA587117
Entities
Organizations
- Coastal Engineering Research Center